diff mbox series

[v2,10/12] HID: input: remove the need for HID_QUIRK_INVERT

Message ID 20220203143226.4023622-11-benjamin.tissoires@redhat.com
State Accepted
Commit 87562fcd134214a68e58d0714b820f2f2da75b1f
Headers show
Series HID: fix for generic input processing | expand

Commit Message

Benjamin Tissoires Feb. 3, 2022, 2:32 p.m. UTC
HID_QUIRK_INVERT is kind of complex to deal with and was bogus.

Furthermore, it didn't make sense to use a global per struct hid_device
quirk for something dynamic as the current state.

Store the current tool information in the report itself, and re-order
the processing of the fields to enforce having all the tablet "state"
fields before getting to In Range and other input fields.

This way, we now have all the information whether a tool is present
or not while processing In Range.

This new behavior enforces that only one tool gets forwarded to userspace
at the same time, and that if either eraser or invert is set, we enforce
BTN_TOOL_RUBBER.

Note that the release of the previous tool now happens in its own EV_SYN
report so userspace doesn't get confused by having 2 tools.

These changes are tested in the following hid-tools regression tests:
https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

Changes in v2:
- rework the entire tool switching, this makes the processing
  slightly more complex but is better for existing userspace.
---
 drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
 include/linux/hid.h     |  6 ++-
 2 files changed, 95 insertions(+), 9 deletions(-)

Comments

Ping Cheng Feb. 10, 2022, 5:21 a.m. UTC | #1
On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> HID_QUIRK_INVERT is kind of complex to deal with and was bogus.
>
> Furthermore, it didn't make sense to use a global per struct hid_device
> quirk for something dynamic as the current state.
>
> Store the current tool information in the report itself, and re-order
> the processing of the fields to enforce having all the tablet "state"
> fields before getting to In Range and other input fields.
>
> This way, we now have all the information whether a tool is present
> or not while processing In Range.
>
> This new behavior enforces that only one tool gets forwarded to userspace
> at the same time, and that if either eraser or invert is set, we enforce
> BTN_TOOL_RUBBER.
>
> Note that the release of the previous tool now happens in its own EV_SYN
> report so userspace doesn't get confused by having 2 tools.
>
> These changes are tested in the following hid-tools regression tests:
> https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
>
> ---
>
> Changes in v2:
> - rework the entire tool switching, this makes the processing
>   slightly more complex but is better for existing userspace.
> ---
>  drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
>  include/linux/hid.h     |  6 ++-
>  2 files changed, 95 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> index 61d91117f4ae..9f8853640648 100644
> --- a/drivers/hid/hid-input.c
> +++ b/drivers/hid/hid-input.c
> @@ -63,8 +63,11 @@ static const struct {
>   * This still leaves us 65535 individual priority values.
>   */
>  static const __u32 hidinput_usages_priorities[] = {
> +       HID_DG_ERASER,          /* Eraser (eraser touching) must always come before tipswitch */
>         HID_DG_INVERT,          /* Invert must always come before In Range */
> -       HID_DG_INRANGE,
> +       HID_DG_TIPSWITCH,       /* Is the tip of the tool touching? */
> +       HID_DG_TIPPRESSURE,     /* Tip Pressure might emulate tip switch */
> +       HID_DG_INRANGE,         /* In Range needs to come after the other tool states */
>  };
>
>  #define map_abs(c)     hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
> @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage,
>         input_event(input, EV_REL, usage->code, hi_res);
>  }
>
> +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
> +                                   unsigned int tool)
> +{
> +       /* if the given tool is not currently reported, ignore */
> +       if (!test_bit(tool, input->key))
> +               return;
> +
> +       /*
> +        * if the given tool was previously set, release it,
> +        * release any TOUCH and send an EV_SYN
> +        */
> +       input_event(input, EV_KEY, BTN_TOUCH, 0);
> +       input_event(input, EV_KEY, tool, 0);

Took a while for me to find the right device and setup the proper
system for the testing. This block missing the serial number:

input_event(input, EV_MSC, MSC_SERIAL, 0);

> +       input_event(input, EV_SYN, SYN_REPORT, 0);
> +
> +       report->tool = 0;
> +}
> +
> +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
> +                               unsigned int new_tool)
> +{
> +       if (report->tool != new_tool)
> +               hid_report_release_tool(report, input, report->tool);
> +
> +       input_event(input, EV_KEY, new_tool, 1);
> +       report->tool = new_tool;
> +}
> +
>  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
>  {
>         struct input_dev *input;
> +       struct hid_report *report = field->report;
>         unsigned *quirks = &hid->quirks;
>
>         if (!usage->type)
> @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
>         }
>
>         switch (usage->hid) {
> +       case HID_DG_ERASER:
> +               report->tool_active |= !!value;
> +
> +               /*
> +                * if eraser is set, we must enforce BTN_TOOL_RUBBER
> +                * to accommodate for devices not following the spec.
> +                */
> +               if (value)
> +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> +               else if (report->tool != BTN_TOOL_RUBBER)
> +                       /* value is off, tool is not rubber, ignore */
> +                       return;
> +
> +               /* let hid-input set BTN_TOUCH */
> +               break;
> +
>         case HID_DG_INVERT:
> -               *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
> +               report->tool_active |= !!value;
> +
> +               /*
> +                * If invert is set, we store BTN_TOOL_RUBBER.
> +                */
> +               if (value)
> +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> +               else if (!report->tool_active)
> +                       /* tool_active not set means Invert and Eraser are not set */
> +                       hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
> +
> +               /* no further processing */
>                 return;
>
>         case HID_DG_INRANGE:
> -               if (value) {
> -                       input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> -                       return;
> +               report->tool_active |= !!value;
> +
> +               if (report->tool_active) {
> +                       /*
> +                        * if tool is not set but is marked as active,
> +                        * assume ours
> +                        */
> +                       if (!report->tool)
> +                               hid_report_set_tool(report, input, usage->code);
> +               } else {
> +                       hid_report_release_tool(report, input, usage->code);
>                 }
> -               input_event(input, usage->type, usage->code, 0);
> -               input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> +
> +               /* reset tool_active for the next event */
> +               report->tool_active = false;
> +
> +               /* no further processing */
>                 return;
>
> +       case HID_DG_TIPSWITCH:
> +               report->tool_active |= !!value;
> +
> +               /* if tool is set to RUBBER we should ignore the current value */
> +               if (report->tool == BTN_TOOL_RUBBER)
> +                       return;
> +
> +               break;
> +
>         case HID_DG_TIPPRESSURE:
>                 if (*quirks & HID_QUIRK_NOTOUCH) {
>                         int a = field->logical_minimum;
>                         int b = field->logical_maximum;
>
> -                       input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
> +                       if (value > a + ((b - a) >> 3)) {
> +                               input_event(input, EV_KEY, BTN_TOUCH, 1);
> +                               report->tool_active = true;
> +                       }
>                 }
>                 break;
>
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index eaad0655b05c..feb8df61168f 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -347,7 +347,7 @@ struct hid_item {
>   */
>  #define MAX_USBHID_BOOT_QUIRKS 4
>
> -#define HID_QUIRK_INVERT                       BIT(0)
> +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
>  #define HID_QUIRK_NOTOUCH                      BIT(1)
>  #define HID_QUIRK_IGNORE                       BIT(2)
>  #define HID_QUIRK_NOGET                                BIT(3)
> @@ -515,6 +515,10 @@ struct hid_report {
>         unsigned maxfield;                              /* maximum valid field index */
>         unsigned size;                                  /* size of the report (bits) */
>         struct hid_device *device;                      /* associated device */
> +
> +       /* tool related state */
> +       bool tool_active;                               /* whether the current tool is active */
> +       unsigned int tool;                              /* BTN_TOOL_* */
>  };
>
>  #define HID_MAX_IDS 256
> --
> 2.33.1
>
Ping Cheng Feb. 10, 2022, 5:43 a.m. UTC | #2
Sorry for the noise. Hit the wrong buttons...

On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
>
> On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> >
> > HID_QUIRK_INVERT is kind of complex to deal with and was bogus.
> >
> > Furthermore, it didn't make sense to use a global per struct hid_device
> > quirk for something dynamic as the current state.
> >
> > Store the current tool information in the report itself, and re-order
> > the processing of the fields to enforce having all the tablet "state"
> > fields before getting to In Range and other input fields.
> >
> > This way, we now have all the information whether a tool is present
> > or not while processing In Range.
> >
> > This new behavior enforces that only one tool gets forwarded to userspace
> > at the same time, and that if either eraser or invert is set, we enforce
> > BTN_TOOL_RUBBER.
> >
> > Note that the release of the previous tool now happens in its own EV_SYN
> > report so userspace doesn't get confused by having 2 tools.
> >
> > These changes are tested in the following hid-tools regression tests:
> > https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
> >
> > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> >
> > ---
> >
> > Changes in v2:
> > - rework the entire tool switching, this makes the processing
> >   slightly more complex but is better for existing userspace.
> > ---
> >  drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
> >  include/linux/hid.h     |  6 ++-
> >  2 files changed, 95 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > index 61d91117f4ae..9f8853640648 100644
> > --- a/drivers/hid/hid-input.c
> > +++ b/drivers/hid/hid-input.c
> > @@ -63,8 +63,11 @@ static const struct {
> >   * This still leaves us 65535 individual priority values.
> >   */
> >  static const __u32 hidinput_usages_priorities[] = {
> > +       HID_DG_ERASER,          /* Eraser (eraser touching) must always come before tipswitch */
> >         HID_DG_INVERT,          /* Invert must always come before In Range */
> > -       HID_DG_INRANGE,
> > +       HID_DG_TIPSWITCH,       /* Is the tip of the tool touching? */
> > +       HID_DG_TIPPRESSURE,     /* Tip Pressure might emulate tip switch */
> > +       HID_DG_INRANGE,         /* In Range needs to come after the other tool states */
> >  };
> >
> >  #define map_abs(c)     hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
> > @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage,
> >         input_event(input, EV_REL, usage->code, hi_res);
> >  }
> >
> > +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
> > +                                   unsigned int tool)
> > +{
> > +       /* if the given tool is not currently reported, ignore */
> > +       if (!test_bit(tool, input->key))
> > +               return;
> > +
> > +       /*
> > +        * if the given tool was previously set, release it,
> > +        * release any TOUCH and send an EV_SYN
> > +        */
> > +       input_event(input, EV_KEY, BTN_TOUCH, 0);
> > +       input_event(input, EV_KEY, tool, 0);

Took a while for me to find the right device and setup the proper
system for the testing. This block missing the serial number:

        input_event(input, EV_MSC, MSC_SERIAL, 0);

Without this line, the next tool will not get its serial number.

> > +       input_event(input, EV_SYN, SYN_REPORT, 0);
> > +
> > +       report->tool = 0;
> > +}
> > +
> > +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
> > +                               unsigned int new_tool)
> > +{
> > +       if (report->tool != new_tool)
> > +               hid_report_release_tool(report, input, report->tool);
> > +
> > +       input_event(input, EV_KEY, new_tool, 1);
> > +       report->tool = new_tool;
> > +}
> > +
> >  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
> >  {
> >         struct input_dev *input;
> > +       struct hid_report *report = field->report;
> >         unsigned *quirks = &hid->quirks;
> >
> >         if (!usage->type)
> > @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
> >         }
> >
> >         switch (usage->hid) {
> > +       case HID_DG_ERASER:
> > +               report->tool_active |= !!value;
> > +
> > +               /*
> > +                * if eraser is set, we must enforce BTN_TOOL_RUBBER
> > +                * to accommodate for devices not following the spec.
> > +                */
> > +               if (value)
> > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > +               else if (report->tool != BTN_TOOL_RUBBER)
> > +                       /* value is off, tool is not rubber, ignore */
> > +                       return;
> > +
> > +               /* let hid-input set BTN_TOUCH */
> > +               break;
> > +
> >         case HID_DG_INVERT:
> > -               *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
> > +               report->tool_active |= !!value;
> > +
> > +               /*
> > +                * If invert is set, we store BTN_TOOL_RUBBER.
> > +                */
> > +               if (value)
> > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > +               else if (!report->tool_active)
> > +                       /* tool_active not set means Invert and Eraser are not set */
> > +                       hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
> > +
> > +               /* no further processing */
> >                 return;
> >
> >         case HID_DG_INRANGE:
> > -               if (value) {
> > -                       input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> > -                       return;
> > +               report->tool_active |= !!value;
> > +
> > +               if (report->tool_active) {
> > +                       /*
> > +                        * if tool is not set but is marked as active,
> > +                        * assume ours
> > +                        */
> > +                       if (!report->tool)
> > +                               hid_report_set_tool(report, input, usage->code);
> > +               } else {
> > +                       hid_report_release_tool(report, input, usage->code);
> >                 }
> > -               input_event(input, usage->type, usage->code, 0);
> > -               input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> > +
> > +               /* reset tool_active for the next event */
> > +               report->tool_active = false;
> > +
> > +               /* no further processing */
> >                 return;
> >
> > +       case HID_DG_TIPSWITCH:
> > +               report->tool_active |= !!value;
> > +
> > +               /* if tool is set to RUBBER we should ignore the current value */
> > +               if (report->tool == BTN_TOOL_RUBBER)
> > +                       return;

This case should return before HID_DG_INVERT is checked since we may
get TIPSWITCH bit before INVERT. In fact, the device that I tested
sends the tipswatch bit before the invert bit. So, I alway get a PEN
in and out before I get ERASER events, when I bring the pen in with
the side-switch/invert bit pressed.

However, we know not all devices support INVERT. We probably have to
keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
wait until HID_DG_INVERT is reached.

If you are interested in the evtest output, please let me know. I'll
share it with you offline so we don't abuse this list...

Cheers,
Ping

> > +               break;
> > +
> >         case HID_DG_TIPPRESSURE:
> >                 if (*quirks & HID_QUIRK_NOTOUCH) {
> >                         int a = field->logical_minimum;
> >                         int b = field->logical_maximum;
> >
> > -                       input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
> > +                       if (value > a + ((b - a) >> 3)) {
> > +                               input_event(input, EV_KEY, BTN_TOUCH, 1);
> > +                               report->tool_active = true;
> > +                       }
> >                 }
> >                 break;
> >
> > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > index eaad0655b05c..feb8df61168f 100644
> > --- a/include/linux/hid.h
> > +++ b/include/linux/hid.h
> > @@ -347,7 +347,7 @@ struct hid_item {
> >   */
> >  #define MAX_USBHID_BOOT_QUIRKS 4
> >
> > -#define HID_QUIRK_INVERT                       BIT(0)
> > +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
> >  #define HID_QUIRK_NOTOUCH                      BIT(1)
> >  #define HID_QUIRK_IGNORE                       BIT(2)
> >  #define HID_QUIRK_NOGET                                BIT(3)
> > @@ -515,6 +515,10 @@ struct hid_report {
> >         unsigned maxfield;                              /* maximum valid field index */
> >         unsigned size;                                  /* size of the report (bits) */
> >         struct hid_device *device;                      /* associated device */
> > +
> > +       /* tool related state */
> > +       bool tool_active;                               /* whether the current tool is active */
> > +       unsigned int tool;                              /* BTN_TOOL_* */
> >  };
> >
> >  #define HID_MAX_IDS 256
> > --
> > 2.33.1
> >
Benjamin Tissoires Feb. 14, 2022, 10:23 a.m. UTC | #3
Hi Ping,

On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
>
> Sorry for the noise. Hit the wrong buttons...
>
> On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> >
> > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > <benjamin.tissoires@redhat.com> wrote:
> > >
> > > HID_QUIRK_INVERT is kind of complex to deal with and was bogus.
> > >
> > > Furthermore, it didn't make sense to use a global per struct hid_device
> > > quirk for something dynamic as the current state.
> > >
> > > Store the current tool information in the report itself, and re-order
> > > the processing of the fields to enforce having all the tablet "state"
> > > fields before getting to In Range and other input fields.
> > >
> > > This way, we now have all the information whether a tool is present
> > > or not while processing In Range.
> > >
> > > This new behavior enforces that only one tool gets forwarded to userspace
> > > at the same time, and that if either eraser or invert is set, we enforce
> > > BTN_TOOL_RUBBER.
> > >
> > > Note that the release of the previous tool now happens in its own EV_SYN
> > > report so userspace doesn't get confused by having 2 tools.
> > >
> > > These changes are tested in the following hid-tools regression tests:
> > > https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
> > >
> > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > >
> > > ---
> > >
> > > Changes in v2:
> > > - rework the entire tool switching, this makes the processing
> > >   slightly more complex but is better for existing userspace.
> > > ---
> > >  drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
> > >  include/linux/hid.h     |  6 ++-
> > >  2 files changed, 95 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > > index 61d91117f4ae..9f8853640648 100644
> > > --- a/drivers/hid/hid-input.c
> > > +++ b/drivers/hid/hid-input.c
> > > @@ -63,8 +63,11 @@ static const struct {
> > >   * This still leaves us 65535 individual priority values.
> > >   */
> > >  static const __u32 hidinput_usages_priorities[] = {
> > > +       HID_DG_ERASER,          /* Eraser (eraser touching) must always come before tipswitch */
> > >         HID_DG_INVERT,          /* Invert must always come before In Range */
> > > -       HID_DG_INRANGE,
> > > +       HID_DG_TIPSWITCH,       /* Is the tip of the tool touching? */
> > > +       HID_DG_TIPPRESSURE,     /* Tip Pressure might emulate tip switch */
> > > +       HID_DG_INRANGE,         /* In Range needs to come after the other tool states */
> > >  };
> > >
> > >  #define map_abs(c)     hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
> > > @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage,
> > >         input_event(input, EV_REL, usage->code, hi_res);
> > >  }
> > >
> > > +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
> > > +                                   unsigned int tool)
> > > +{
> > > +       /* if the given tool is not currently reported, ignore */
> > > +       if (!test_bit(tool, input->key))
> > > +               return;
> > > +
> > > +       /*
> > > +        * if the given tool was previously set, release it,
> > > +        * release any TOUCH and send an EV_SYN
> > > +        */
> > > +       input_event(input, EV_KEY, BTN_TOUCH, 0);
> > > +       input_event(input, EV_KEY, tool, 0);
>
> Took a while for me to find the right device and setup the proper
> system for the testing. This block missing the serial number:
>
>         input_event(input, EV_MSC, MSC_SERIAL, 0);
>
> Without this line, the next tool will not get its serial number.

I am tempted to simply disregard this request. It has been known for
ages that the evdev values are cached, so if you do not have the value
you need that means that the value has been sent previously (or you
can request it upon start with an ioctl). So in this particular case,
I don't really see the logic in forcing the SERIAL into the TOOL type
when the tool is clearly unrelated to the serial.

My fear here is that by linking together too many axes, we may enter
in a state where we can not untangle them when needed.

>
> > > +       input_event(input, EV_SYN, SYN_REPORT, 0);
> > > +
> > > +       report->tool = 0;
> > > +}
> > > +
> > > +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
> > > +                               unsigned int new_tool)
> > > +{
> > > +       if (report->tool != new_tool)
> > > +               hid_report_release_tool(report, input, report->tool);
> > > +
> > > +       input_event(input, EV_KEY, new_tool, 1);
> > > +       report->tool = new_tool;
> > > +}
> > > +
> > >  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
> > >  {
> > >         struct input_dev *input;
> > > +       struct hid_report *report = field->report;
> > >         unsigned *quirks = &hid->quirks;
> > >
> > >         if (!usage->type)
> > > @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
> > >         }
> > >
> > >         switch (usage->hid) {
> > > +       case HID_DG_ERASER:
> > > +               report->tool_active |= !!value;
> > > +
> > > +               /*
> > > +                * if eraser is set, we must enforce BTN_TOOL_RUBBER
> > > +                * to accommodate for devices not following the spec.
> > > +                */
> > > +               if (value)
> > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > +               else if (report->tool != BTN_TOOL_RUBBER)
> > > +                       /* value is off, tool is not rubber, ignore */
> > > +                       return;
> > > +
> > > +               /* let hid-input set BTN_TOUCH */
> > > +               break;
> > > +
> > >         case HID_DG_INVERT:
> > > -               *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
> > > +               report->tool_active |= !!value;
> > > +
> > > +               /*
> > > +                * If invert is set, we store BTN_TOOL_RUBBER.
> > > +                */
> > > +               if (value)
> > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > +               else if (!report->tool_active)
> > > +                       /* tool_active not set means Invert and Eraser are not set */
> > > +                       hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
> > > +
> > > +               /* no further processing */
> > >                 return;
> > >
> > >         case HID_DG_INRANGE:
> > > -               if (value) {
> > > -                       input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> > > -                       return;
> > > +               report->tool_active |= !!value;
> > > +
> > > +               if (report->tool_active) {
> > > +                       /*
> > > +                        * if tool is not set but is marked as active,
> > > +                        * assume ours
> > > +                        */
> > > +                       if (!report->tool)
> > > +                               hid_report_set_tool(report, input, usage->code);
> > > +               } else {
> > > +                       hid_report_release_tool(report, input, usage->code);
> > >                 }
> > > -               input_event(input, usage->type, usage->code, 0);
> > > -               input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> > > +
> > > +               /* reset tool_active for the next event */
> > > +               report->tool_active = false;
> > > +
> > > +               /* no further processing */
> > >                 return;
> > >
> > > +       case HID_DG_TIPSWITCH:
> > > +               report->tool_active |= !!value;
> > > +
> > > +               /* if tool is set to RUBBER we should ignore the current value */
> > > +               if (report->tool == BTN_TOOL_RUBBER)
> > > +                       return;
>
> This case should return before HID_DG_INVERT is checked since we may
> get TIPSWITCH bit before INVERT. In fact, the device that I tested
> sends the tipswatch bit before the invert bit. So, I alway get a PEN
> in and out before I get ERASER events, when I bring the pen in with
> the side-switch/invert bit pressed.
>
> However, we know not all devices support INVERT. We probably have to
> keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> wait until HID_DG_INVERT is reached.

I am under the impression that you completely missed the point of the
patch series. This series re-orders the processing of the events, and
if you look at the very first hunk in this patch, you'll see that the
new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
matter the order of the device.

So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
is set, either INVERT or ERASER is set to 1, whether or not they come
before or after in the report.

>
> If you are interested in the evtest output, please let me know. I'll
> share it with you offline so we don't abuse this list...

evtest is the output of the kernel, and it doesn't give me much more
than "it's broken". However, if you can give me the hid-recorder
outputs, I'll be able to reproduce locally and compare the output as I
fix the code. Of course the best would be to add test cases in the
hid-tools repo, but I'll need the hid-recorder anyway to understand
what is failing and to be able to write the tests.

Cheers,
Benjamin

>
> Cheers,
> Ping
>
> > > +               break;
> > > +
> > >         case HID_DG_TIPPRESSURE:
> > >                 if (*quirks & HID_QUIRK_NOTOUCH) {
> > >                         int a = field->logical_minimum;
> > >                         int b = field->logical_maximum;
> > >
> > > -                       input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
> > > +                       if (value > a + ((b - a) >> 3)) {
> > > +                               input_event(input, EV_KEY, BTN_TOUCH, 1);
> > > +                               report->tool_active = true;
> > > +                       }
> > >                 }
> > >                 break;
> > >
> > > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > > index eaad0655b05c..feb8df61168f 100644
> > > --- a/include/linux/hid.h
> > > +++ b/include/linux/hid.h
> > > @@ -347,7 +347,7 @@ struct hid_item {
> > >   */
> > >  #define MAX_USBHID_BOOT_QUIRKS 4
> > >
> > > -#define HID_QUIRK_INVERT                       BIT(0)
> > > +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
> > >  #define HID_QUIRK_NOTOUCH                      BIT(1)
> > >  #define HID_QUIRK_IGNORE                       BIT(2)
> > >  #define HID_QUIRK_NOGET                                BIT(3)
> > > @@ -515,6 +515,10 @@ struct hid_report {
> > >         unsigned maxfield;                              /* maximum valid field index */
> > >         unsigned size;                                  /* size of the report (bits) */
> > >         struct hid_device *device;                      /* associated device */
> > > +
> > > +       /* tool related state */
> > > +       bool tool_active;                               /* whether the current tool is active */
> > > +       unsigned int tool;                              /* BTN_TOOL_* */
> > >  };
> > >
> > >  #define HID_MAX_IDS 256
> > > --
> > > 2.33.1
> > >
>
Ping Cheng Feb. 15, 2022, 2:04 a.m. UTC | #4
On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Hi Ping,
>
> On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> >
> > Sorry for the noise. Hit the wrong buttons...
> >
> > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > >
> > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > <benjamin.tissoires@redhat.com> wrote:
> > > >
> > > > HID_QUIRK_INVERT is kind of complex to deal with and was bogus.
> > > >
> > > > Furthermore, it didn't make sense to use a global per struct hid_device
> > > > quirk for something dynamic as the current state.
> > > >
> > > > Store the current tool information in the report itself, and re-order
> > > > the processing of the fields to enforce having all the tablet "state"
> > > > fields before getting to In Range and other input fields.
> > > >
> > > > This way, we now have all the information whether a tool is present
> > > > or not while processing In Range.
> > > >
> > > > This new behavior enforces that only one tool gets forwarded to userspace
> > > > at the same time, and that if either eraser or invert is set, we enforce
> > > > BTN_TOOL_RUBBER.
> > > >
> > > > Note that the release of the previous tool now happens in its own EV_SYN
> > > > report so userspace doesn't get confused by having 2 tools.
> > > >
> > > > These changes are tested in the following hid-tools regression tests:
> > > > https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
> > > >
> > > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > > >
> > > > ---
> > > >
> > > > Changes in v2:
> > > > - rework the entire tool switching, this makes the processing
> > > >   slightly more complex but is better for existing userspace.
> > > > ---
> > > >  drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
> > > >  include/linux/hid.h     |  6 ++-
> > > >  2 files changed, 95 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > > > index 61d91117f4ae..9f8853640648 100644
> > > > --- a/drivers/hid/hid-input.c
> > > > +++ b/drivers/hid/hid-input.c
> > > > @@ -63,8 +63,11 @@ static const struct {
> > > >   * This still leaves us 65535 individual priority values.
> > > >   */
> > > >  static const __u32 hidinput_usages_priorities[] = {
> > > > +       HID_DG_ERASER,          /* Eraser (eraser touching) must always come before tipswitch */
> > > >         HID_DG_INVERT,          /* Invert must always come before In Range */
> > > > -       HID_DG_INRANGE,
> > > > +       HID_DG_TIPSWITCH,       /* Is the tip of the tool touching? */
> > > > +       HID_DG_TIPPRESSURE,     /* Tip Pressure might emulate tip switch */
> > > > +       HID_DG_INRANGE,         /* In Range needs to come after the other tool states */
> > > >  };
> > > >
> > > >  #define map_abs(c)     hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
> > > > @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage,
> > > >         input_event(input, EV_REL, usage->code, hi_res);
> > > >  }
> > > >
> > > > +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
> > > > +                                   unsigned int tool)
> > > > +{
> > > > +       /* if the given tool is not currently reported, ignore */
> > > > +       if (!test_bit(tool, input->key))
> > > > +               return;
> > > > +
> > > > +       /*
> > > > +        * if the given tool was previously set, release it,
> > > > +        * release any TOUCH and send an EV_SYN
> > > > +        */
> > > > +       input_event(input, EV_KEY, BTN_TOUCH, 0);
> > > > +       input_event(input, EV_KEY, tool, 0);
> >
> > Took a while for me to find the right device and setup the proper
> > system for the testing. This block missing the serial number:
> >
> >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> >
> > Without this line, the next tool will not get its serial number.
>
> I am tempted to simply disregard this request. It has been known for
> ages that the evdev values are cached, so if you do not have the value
> you need that means that the value has been sent previously (or you
> can request it upon start with an ioctl). So in this particular case,
> I don't really see the logic in forcing the SERIAL into the TOOL type
> when the tool is clearly unrelated to the serial.
>
> My fear here is that by linking together too many axes, we may enter
> in a state where we can not untangle them when needed.

I see your point. We indeed added those ioctl's in the X driver to
avoid missing the initial states of some of the key events.

> >
> > > > +       input_event(input, EV_SYN, SYN_REPORT, 0);
> > > > +
> > > > +       report->tool = 0;
> > > > +}
> > > > +
> > > > +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
> > > > +                               unsigned int new_tool)
> > > > +{
> > > > +       if (report->tool != new_tool)
> > > > +               hid_report_release_tool(report, input, report->tool);
> > > > +
> > > > +       input_event(input, EV_KEY, new_tool, 1);
> > > > +       report->tool = new_tool;
> > > > +}
> > > > +
> > > >  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
> > > >  {
> > > >         struct input_dev *input;
> > > > +       struct hid_report *report = field->report;
> > > >         unsigned *quirks = &hid->quirks;
> > > >
> > > >         if (!usage->type)
> > > > @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
> > > >         }
> > > >
> > > >         switch (usage->hid) {
> > > > +       case HID_DG_ERASER:
> > > > +               report->tool_active |= !!value;
> > > > +
> > > > +               /*
> > > > +                * if eraser is set, we must enforce BTN_TOOL_RUBBER
> > > > +                * to accommodate for devices not following the spec.
> > > > +                */
> > > > +               if (value)
> > > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > > +               else if (report->tool != BTN_TOOL_RUBBER)
> > > > +                       /* value is off, tool is not rubber, ignore */
> > > > +                       return;
> > > > +
> > > > +               /* let hid-input set BTN_TOUCH */
> > > > +               break;
> > > > +
> > > >         case HID_DG_INVERT:
> > > > -               *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
> > > > +               report->tool_active |= !!value;
> > > > +
> > > > +               /*
> > > > +                * If invert is set, we store BTN_TOOL_RUBBER.
> > > > +                */
> > > > +               if (value)
> > > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > > +               else if (!report->tool_active)
> > > > +                       /* tool_active not set means Invert and Eraser are not set */
> > > > +                       hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
> > > > +
> > > > +               /* no further processing */
> > > >                 return;
> > > >
> > > >         case HID_DG_INRANGE:
> > > > -               if (value) {
> > > > -                       input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> > > > -                       return;
> > > > +               report->tool_active |= !!value;
> > > > +
> > > > +               if (report->tool_active) {
> > > > +                       /*
> > > > +                        * if tool is not set but is marked as active,
> > > > +                        * assume ours
> > > > +                        */
> > > > +                       if (!report->tool)
> > > > +                               hid_report_set_tool(report, input, usage->code);
> > > > +               } else {
> > > > +                       hid_report_release_tool(report, input, usage->code);
> > > >                 }
> > > > -               input_event(input, usage->type, usage->code, 0);
> > > > -               input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> > > > +
> > > > +               /* reset tool_active for the next event */
> > > > +               report->tool_active = false;
> > > > +
> > > > +               /* no further processing */
> > > >                 return;
> > > >
> > > > +       case HID_DG_TIPSWITCH:
> > > > +               report->tool_active |= !!value;
> > > > +
> > > > +               /* if tool is set to RUBBER we should ignore the current value */
> > > > +               if (report->tool == BTN_TOOL_RUBBER)
> > > > +                       return;
> >
> > This case should return before HID_DG_INVERT is checked since we may
> > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > in and out before I get ERASER events, when I bring the pen in with
> > the side-switch/invert bit pressed.
> >
> > However, we know not all devices support INVERT. We probably have to
> > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > wait until HID_DG_INVERT is reached.
>
> I am under the impression that you completely missed the point of the
> patch series. This series re-orders the processing of the events, and
> if you look at the very first hunk in this patch, you'll see that the
> new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> matter the order of the device.

Yeah, I read that part of the code, more than once. But, my evtest
gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
confused too. Then I thought maybe the code still relies on the actual
order of the usages. Anyway, we've done enough discussion and testing,
let's move on. The patchset is:

Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Tested-by: Ping Cheng <ping.cheng@wacom.com>

Thank you for your effort, Benjamin!
Ping

> So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> is set, either INVERT or ERASER is set to 1, whether or not they come
> before or after in the report.
>
> >
> > If you are interested in the evtest output, please let me know. I'll
> > share it with you offline so we don't abuse this list...
>
> evtest is the output of the kernel, and it doesn't give me much more
> than "it's broken". However, if you can give me the hid-recorder
> outputs, I'll be able to reproduce locally and compare the output as I
> fix the code. Of course the best would be to add test cases in the
> hid-tools repo, but I'll need the hid-recorder anyway to understand
> what is failing and to be able to write the tests.
>
> Cheers,
> Benjamin
>
> >
> > Cheers,
> > Ping
> >
> > > > +               break;
> > > > +
> > > >         case HID_DG_TIPPRESSURE:
> > > >                 if (*quirks & HID_QUIRK_NOTOUCH) {
> > > >                         int a = field->logical_minimum;
> > > >                         int b = field->logical_maximum;
> > > >
> > > > -                       input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
> > > > +                       if (value > a + ((b - a) >> 3)) {
> > > > +                               input_event(input, EV_KEY, BTN_TOUCH, 1);
> > > > +                               report->tool_active = true;
> > > > +                       }
> > > >                 }
> > > >                 break;
> > > >
> > > > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > > > index eaad0655b05c..feb8df61168f 100644
> > > > --- a/include/linux/hid.h
> > > > +++ b/include/linux/hid.h
> > > > @@ -347,7 +347,7 @@ struct hid_item {
> > > >   */
> > > >  #define MAX_USBHID_BOOT_QUIRKS 4
> > > >
> > > > -#define HID_QUIRK_INVERT                       BIT(0)
> > > > +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
> > > >  #define HID_QUIRK_NOTOUCH                      BIT(1)
> > > >  #define HID_QUIRK_IGNORE                       BIT(2)
> > > >  #define HID_QUIRK_NOGET                                BIT(3)
> > > > @@ -515,6 +515,10 @@ struct hid_report {
> > > >         unsigned maxfield;                              /* maximum valid field index */
> > > >         unsigned size;                                  /* size of the report (bits) */
> > > >         struct hid_device *device;                      /* associated device */
> > > > +
> > > > +       /* tool related state */
> > > > +       bool tool_active;                               /* whether the current tool is active */
> > > > +       unsigned int tool;                              /* BTN_TOOL_* */
> > > >  };
> > > >
> > > >  #define HID_MAX_IDS 256
> > > > --
> > > > 2.33.1
> > > >
> >
>
Benjamin Tissoires Feb. 15, 2022, 8:51 a.m. UTC | #5
On Tue, Feb 15, 2022 at 3:04 AM Ping Cheng <pinglinux@gmail.com> wrote:
>
> On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> >
> > Hi Ping,
> >
> > On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> > >
> > > Sorry for the noise. Hit the wrong buttons...
> > >
> > > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > > >
> > > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > > <benjamin.tissoires@redhat.com> wrote:
> > > > >
> > > > > HID_QUIRK_INVERT is kind of complex to deal with and was bogus.
> > > > >
> > > > > Furthermore, it didn't make sense to use a global per struct hid_device
> > > > > quirk for something dynamic as the current state.
> > > > >
> > > > > Store the current tool information in the report itself, and re-order
> > > > > the processing of the fields to enforce having all the tablet "state"
> > > > > fields before getting to In Range and other input fields.
> > > > >
> > > > > This way, we now have all the information whether a tool is present
> > > > > or not while processing In Range.
> > > > >
> > > > > This new behavior enforces that only one tool gets forwarded to userspace
> > > > > at the same time, and that if either eraser or invert is set, we enforce
> > > > > BTN_TOOL_RUBBER.
> > > > >
> > > > > Note that the release of the previous tool now happens in its own EV_SYN
> > > > > report so userspace doesn't get confused by having 2 tools.
> > > > >
> > > > > These changes are tested in the following hid-tools regression tests:
> > > > > https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
> > > > >
> > > > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > > > >
> > > > > ---
> > > > >
> > > > > Changes in v2:
> > > > > - rework the entire tool switching, this makes the processing
> > > > >   slightly more complex but is better for existing userspace.
> > > > > ---
> > > > >  drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++----
> > > > >  include/linux/hid.h     |  6 ++-
> > > > >  2 files changed, 95 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
> > > > > index 61d91117f4ae..9f8853640648 100644
> > > > > --- a/drivers/hid/hid-input.c
> > > > > +++ b/drivers/hid/hid-input.c
> > > > > @@ -63,8 +63,11 @@ static const struct {
> > > > >   * This still leaves us 65535 individual priority values.
> > > > >   */
> > > > >  static const __u32 hidinput_usages_priorities[] = {
> > > > > +       HID_DG_ERASER,          /* Eraser (eraser touching) must always come before tipswitch */
> > > > >         HID_DG_INVERT,          /* Invert must always come before In Range */
> > > > > -       HID_DG_INRANGE,
> > > > > +       HID_DG_TIPSWITCH,       /* Is the tip of the tool touching? */
> > > > > +       HID_DG_TIPPRESSURE,     /* Tip Pressure might emulate tip switch */
> > > > > +       HID_DG_INRANGE,         /* In Range needs to come after the other tool states */
> > > > >  };
> > > > >
> > > > >  #define map_abs(c)     hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
> > > > > @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage,
> > > > >         input_event(input, EV_REL, usage->code, hi_res);
> > > > >  }
> > > > >
> > > > > +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
> > > > > +                                   unsigned int tool)
> > > > > +{
> > > > > +       /* if the given tool is not currently reported, ignore */
> > > > > +       if (!test_bit(tool, input->key))
> > > > > +               return;
> > > > > +
> > > > > +       /*
> > > > > +        * if the given tool was previously set, release it,
> > > > > +        * release any TOUCH and send an EV_SYN
> > > > > +        */
> > > > > +       input_event(input, EV_KEY, BTN_TOUCH, 0);
> > > > > +       input_event(input, EV_KEY, tool, 0);
> > >
> > > Took a while for me to find the right device and setup the proper
> > > system for the testing. This block missing the serial number:
> > >
> > >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> > >
> > > Without this line, the next tool will not get its serial number.
> >
> > I am tempted to simply disregard this request. It has been known for
> > ages that the evdev values are cached, so if you do not have the value
> > you need that means that the value has been sent previously (or you
> > can request it upon start with an ioctl). So in this particular case,
> > I don't really see the logic in forcing the SERIAL into the TOOL type
> > when the tool is clearly unrelated to the serial.
> >
> > My fear here is that by linking together too many axes, we may enter
> > in a state where we can not untangle them when needed.
>
> I see your point. We indeed added those ioctl's in the X driver to
> avoid missing the initial states of some of the key events.
>
> > >
> > > > > +       input_event(input, EV_SYN, SYN_REPORT, 0);
> > > > > +
> > > > > +       report->tool = 0;
> > > > > +}
> > > > > +
> > > > > +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
> > > > > +                               unsigned int new_tool)
> > > > > +{
> > > > > +       if (report->tool != new_tool)
> > > > > +               hid_report_release_tool(report, input, report->tool);
> > > > > +
> > > > > +       input_event(input, EV_KEY, new_tool, 1);
> > > > > +       report->tool = new_tool;
> > > > > +}
> > > > > +
> > > > >  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
> > > > >  {
> > > > >         struct input_dev *input;
> > > > > +       struct hid_report *report = field->report;
> > > > >         unsigned *quirks = &hid->quirks;
> > > > >
> > > > >         if (!usage->type)
> > > > > @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
> > > > >         }
> > > > >
> > > > >         switch (usage->hid) {
> > > > > +       case HID_DG_ERASER:
> > > > > +               report->tool_active |= !!value;
> > > > > +
> > > > > +               /*
> > > > > +                * if eraser is set, we must enforce BTN_TOOL_RUBBER
> > > > > +                * to accommodate for devices not following the spec.
> > > > > +                */
> > > > > +               if (value)
> > > > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > > > +               else if (report->tool != BTN_TOOL_RUBBER)
> > > > > +                       /* value is off, tool is not rubber, ignore */
> > > > > +                       return;
> > > > > +
> > > > > +               /* let hid-input set BTN_TOUCH */
> > > > > +               break;
> > > > > +
> > > > >         case HID_DG_INVERT:
> > > > > -               *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
> > > > > +               report->tool_active |= !!value;
> > > > > +
> > > > > +               /*
> > > > > +                * If invert is set, we store BTN_TOOL_RUBBER.
> > > > > +                */
> > > > > +               if (value)
> > > > > +                       hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
> > > > > +               else if (!report->tool_active)
> > > > > +                       /* tool_active not set means Invert and Eraser are not set */
> > > > > +                       hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
> > > > > +
> > > > > +               /* no further processing */
> > > > >                 return;
> > > > >
> > > > >         case HID_DG_INRANGE:
> > > > > -               if (value) {
> > > > > -                       input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
> > > > > -                       return;
> > > > > +               report->tool_active |= !!value;
> > > > > +
> > > > > +               if (report->tool_active) {
> > > > > +                       /*
> > > > > +                        * if tool is not set but is marked as active,
> > > > > +                        * assume ours
> > > > > +                        */
> > > > > +                       if (!report->tool)
> > > > > +                               hid_report_set_tool(report, input, usage->code);
> > > > > +               } else {
> > > > > +                       hid_report_release_tool(report, input, usage->code);
> > > > >                 }
> > > > > -               input_event(input, usage->type, usage->code, 0);
> > > > > -               input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
> > > > > +
> > > > > +               /* reset tool_active for the next event */
> > > > > +               report->tool_active = false;
> > > > > +
> > > > > +               /* no further processing */
> > > > >                 return;
> > > > >
> > > > > +       case HID_DG_TIPSWITCH:
> > > > > +               report->tool_active |= !!value;
> > > > > +
> > > > > +               /* if tool is set to RUBBER we should ignore the current value */
> > > > > +               if (report->tool == BTN_TOOL_RUBBER)
> > > > > +                       return;
> > >
> > > This case should return before HID_DG_INVERT is checked since we may
> > > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > > in and out before I get ERASER events, when I bring the pen in with
> > > the side-switch/invert bit pressed.
> > >
> > > However, we know not all devices support INVERT. We probably have to
> > > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > > wait until HID_DG_INVERT is reached.
> >
> > I am under the impression that you completely missed the point of the
> > patch series. This series re-orders the processing of the events, and
> > if you look at the very first hunk in this patch, you'll see that the
> > new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> > matter the order of the device.
>
> Yeah, I read that part of the code, more than once. But, my evtest
> gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
> confused too. Then I thought maybe the code still relies on the actual
> order of the usages. Anyway, we've done enough discussion and testing,
> let's move on. The patchset is:
>
> Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
> Tested-by: Ping Cheng <ping.cheng@wacom.com>

Thanks for the review.

 However, if the device is not working as expected, can you send me
the hid-recorder[0] output off list so I can diagnose what is
happening?

Cheers,
Benjamin

[0] clone https://gitlab.freedesktop.org/libevdev/hid-tools, then pip
install ., then `sudo hid-recorder`

>
> Thank you for your effort, Benjamin!
> Ping
>
> > So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> > is set, either INVERT or ERASER is set to 1, whether or not they come
> > before or after in the report.
> >
> > >
> > > If you are interested in the evtest output, please let me know. I'll
> > > share it with you offline so we don't abuse this list...
> >
> > evtest is the output of the kernel, and it doesn't give me much more
> > than "it's broken". However, if you can give me the hid-recorder
> > outputs, I'll be able to reproduce locally and compare the output as I
> > fix the code. Of course the best would be to add test cases in the
> > hid-tools repo, but I'll need the hid-recorder anyway to understand
> > what is failing and to be able to write the tests.
> >
> > Cheers,
> > Benjamin
> >
> > >
> > > Cheers,
> > > Ping
> > >
> > > > > +               break;
> > > > > +
> > > > >         case HID_DG_TIPPRESSURE:
> > > > >                 if (*quirks & HID_QUIRK_NOTOUCH) {
> > > > >                         int a = field->logical_minimum;
> > > > >                         int b = field->logical_maximum;
> > > > >
> > > > > -                       input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
> > > > > +                       if (value > a + ((b - a) >> 3)) {
> > > > > +                               input_event(input, EV_KEY, BTN_TOUCH, 1);
> > > > > +                               report->tool_active = true;
> > > > > +                       }
> > > > >                 }
> > > > >                 break;
> > > > >
> > > > > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > > > > index eaad0655b05c..feb8df61168f 100644
> > > > > --- a/include/linux/hid.h
> > > > > +++ b/include/linux/hid.h
> > > > > @@ -347,7 +347,7 @@ struct hid_item {
> > > > >   */
> > > > >  #define MAX_USBHID_BOOT_QUIRKS 4
> > > > >
> > > > > -#define HID_QUIRK_INVERT                       BIT(0)
> > > > > +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
> > > > >  #define HID_QUIRK_NOTOUCH                      BIT(1)
> > > > >  #define HID_QUIRK_IGNORE                       BIT(2)
> > > > >  #define HID_QUIRK_NOGET                                BIT(3)
> > > > > @@ -515,6 +515,10 @@ struct hid_report {
> > > > >         unsigned maxfield;                              /* maximum valid field index */
> > > > >         unsigned size;                                  /* size of the report (bits) */
> > > > >         struct hid_device *device;                      /* associated device */
> > > > > +
> > > > > +       /* tool related state */
> > > > > +       bool tool_active;                               /* whether the current tool is active */
> > > > > +       unsigned int tool;                              /* BTN_TOOL_* */
> > > > >  };
> > > > >
> > > > >  #define HID_MAX_IDS 256
> > > > > --
> > > > > 2.33.1
> > > > >
> > >
> >
>
diff mbox series

Patch

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 61d91117f4ae..9f8853640648 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -63,8 +63,11 @@  static const struct {
  * This still leaves us 65535 individual priority values.
  */
 static const __u32 hidinput_usages_priorities[] = {
+	HID_DG_ERASER,		/* Eraser (eraser touching) must always come before tipswitch */
 	HID_DG_INVERT,		/* Invert must always come before In Range */
-	HID_DG_INRANGE,
+	HID_DG_TIPSWITCH,	/* Is the tip of the tool touching? */
+	HID_DG_TIPPRESSURE,	/* Tip Pressure might emulate tip switch */
+	HID_DG_INRANGE,		/* In Range needs to come after the other tool states */
 };
 
 #define map_abs(c)	hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c))
@@ -1365,9 +1368,38 @@  static void hidinput_handle_scroll(struct hid_usage *usage,
 	input_event(input, EV_REL, usage->code, hi_res);
 }
 
+static void hid_report_release_tool(struct hid_report *report, struct input_dev *input,
+				    unsigned int tool)
+{
+	/* if the given tool is not currently reported, ignore */
+	if (!test_bit(tool, input->key))
+		return;
+
+	/*
+	 * if the given tool was previously set, release it,
+	 * release any TOUCH and send an EV_SYN
+	 */
+	input_event(input, EV_KEY, BTN_TOUCH, 0);
+	input_event(input, EV_KEY, tool, 0);
+	input_event(input, EV_SYN, SYN_REPORT, 0);
+
+	report->tool = 0;
+}
+
+static void hid_report_set_tool(struct hid_report *report, struct input_dev *input,
+				unsigned int new_tool)
+{
+	if (report->tool != new_tool)
+		hid_report_release_tool(report, input, report->tool);
+
+	input_event(input, EV_KEY, new_tool, 1);
+	report->tool = new_tool;
+}
+
 void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value)
 {
 	struct input_dev *input;
+	struct hid_report *report = field->report;
 	unsigned *quirks = &hid->quirks;
 
 	if (!usage->type)
@@ -1418,25 +1450,75 @@  void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
 	}
 
 	switch (usage->hid) {
+	case HID_DG_ERASER:
+		report->tool_active |= !!value;
+
+		/*
+		 * if eraser is set, we must enforce BTN_TOOL_RUBBER
+		 * to accommodate for devices not following the spec.
+		 */
+		if (value)
+			hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
+		else if (report->tool != BTN_TOOL_RUBBER)
+			/* value is off, tool is not rubber, ignore */
+			return;
+
+		/* let hid-input set BTN_TOUCH */
+		break;
+
 	case HID_DG_INVERT:
-		*quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT);
+		report->tool_active |= !!value;
+
+		/*
+		 * If invert is set, we store BTN_TOOL_RUBBER.
+		 */
+		if (value)
+			hid_report_set_tool(report, input, BTN_TOOL_RUBBER);
+		else if (!report->tool_active)
+			/* tool_active not set means Invert and Eraser are not set */
+			hid_report_release_tool(report, input, BTN_TOOL_RUBBER);
+
+		/* no further processing */
 		return;
 
 	case HID_DG_INRANGE:
-		if (value) {
-			input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1);
-			return;
+		report->tool_active |= !!value;
+
+		if (report->tool_active) {
+			/*
+			 * if tool is not set but is marked as active,
+			 * assume ours
+			 */
+			if (!report->tool)
+				hid_report_set_tool(report, input, usage->code);
+		} else {
+			hid_report_release_tool(report, input, usage->code);
 		}
-		input_event(input, usage->type, usage->code, 0);
-		input_event(input, usage->type, BTN_TOOL_RUBBER, 0);
+
+		/* reset tool_active for the next event */
+		report->tool_active = false;
+
+		/* no further processing */
 		return;
 
+	case HID_DG_TIPSWITCH:
+		report->tool_active |= !!value;
+
+		/* if tool is set to RUBBER we should ignore the current value */
+		if (report->tool == BTN_TOOL_RUBBER)
+			return;
+
+		break;
+
 	case HID_DG_TIPPRESSURE:
 		if (*quirks & HID_QUIRK_NOTOUCH) {
 			int a = field->logical_minimum;
 			int b = field->logical_maximum;
 
-			input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3));
+			if (value > a + ((b - a) >> 3)) {
+				input_event(input, EV_KEY, BTN_TOUCH, 1);
+				report->tool_active = true;
+			}
 		}
 		break;
 
diff --git a/include/linux/hid.h b/include/linux/hid.h
index eaad0655b05c..feb8df61168f 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -347,7 +347,7 @@  struct hid_item {
  */
 #define MAX_USBHID_BOOT_QUIRKS 4
 
-#define HID_QUIRK_INVERT			BIT(0)
+/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */
 #define HID_QUIRK_NOTOUCH			BIT(1)
 #define HID_QUIRK_IGNORE			BIT(2)
 #define HID_QUIRK_NOGET				BIT(3)
@@ -515,6 +515,10 @@  struct hid_report {
 	unsigned maxfield;				/* maximum valid field index */
 	unsigned size;					/* size of the report (bits) */
 	struct hid_device *device;			/* associated device */
+
+	/* tool related state */
+	bool tool_active;				/* whether the current tool is active */
+	unsigned int tool;				/* BTN_TOOL_* */
 };
 
 #define HID_MAX_IDS 256