| Message ID | 1657891312-21748-1-git-send-email-quic_kriskura@quicinc.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly | expand |
On Fri, Jul 15, 2022 at 06:51:52PM +0530, Krishna Kurapati wrote: > Subject: usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly nit: "isn't probed properly" sounds like a bug or HW issue. In case you re-spin maybe change it to "hasn't probed yet" or similar. > On SC7180 devices, it is observed that dwc3 probing is deferred > because device_links_check_suppliers() finds that '88e3000.phy' > isn't ready yet. > > As a part of its probe call, dwc3-qcom driver checks if dwc3 core > is wakeup capable or not. If the dwc3 core is wakeup capable, driver > configures dwc-qcom's power domain to be always ON. Also it configures > dp/dm interrupts accordingly to support wakeup from system suspend. > > More info regarding the same can be found at: > commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") > commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") > > In the event, dwc3 probe gets deferred and is processed after dwc3-qcom > probe, driver ends up reading the wakeup capability of dwc3 core as false > leading to instability in suspend/resume path. > > To avoid this scenario, ensure dwc3_probe is successful by checking > if appropriate driver is assigned to it or not after the of_platform_populate > call. If it isn't then defer dwc3-qcom probe as well. > > Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") > Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> Reported-by: Matthias Kaehlcke <mka@chromium.org> Tested-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Please make sure to add reviewers of previous versions or other folks you would like to review your patches in cc. I found v2 accidentally while looking for something else.
On 7/16/2022 2:11 AM, Matthias Kaehlcke wrote: > On Fri, Jul 15, 2022 at 06:51:52PM +0530, Krishna Kurapati wrote: > >> Subject: usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly > nit: "isn't probed properly" sounds like a bug or HW issue. In case > you re-spin maybe change it to "hasn't probed yet" or similar. > >> On SC7180 devices, it is observed that dwc3 probing is deferred >> because device_links_check_suppliers() finds that '88e3000.phy' >> isn't ready yet. >> >> As a part of its probe call, dwc3-qcom driver checks if dwc3 core >> is wakeup capable or not. If the dwc3 core is wakeup capable, driver >> configures dwc-qcom's power domain to be always ON. Also it configures >> dp/dm interrupts accordingly to support wakeup from system suspend. >> >> More info regarding the same can be found at: >> commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") >> commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") >> >> In the event, dwc3 probe gets deferred and is processed after dwc3-qcom >> probe, driver ends up reading the wakeup capability of dwc3 core as false >> leading to instability in suspend/resume path. >> >> To avoid this scenario, ensure dwc3_probe is successful by checking >> if appropriate driver is assigned to it or not after the of_platform_populate >> call. If it isn't then defer dwc3-qcom probe as well. >> >> Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") >> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> > Reported-by: Matthias Kaehlcke <mka@chromium.org> > Tested-by: Matthias Kaehlcke <mka@chromium.org> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > > Please make sure to add reviewers of previous versions or other folks you > would like to review your patches in cc. I found v2 accidentally while > looking for something else. Hi Mathias, Sure, Thanks for the review.
On Fri, Jul 15, 2022 at 01:41:57PM -0700, Matthias Kaehlcke wrote: > On Fri, Jul 15, 2022 at 06:51:52PM +0530, Krishna Kurapati wrote: > > > Subject: usb: dwc3: qcom: Defer dwc3-qcom probe if dwc3 isn't probed properly > > nit: "isn't probed properly" sounds like a bug or HW issue. In case > you re-spin maybe change it to "hasn't probed yet" or similar. > > > On SC7180 devices, it is observed that dwc3 probing is deferred > > because device_links_check_suppliers() finds that '88e3000.phy' > > isn't ready yet. > > > > As a part of its probe call, dwc3-qcom driver checks if dwc3 core > > is wakeup capable or not. If the dwc3 core is wakeup capable, driver > > configures dwc-qcom's power domain to be always ON. Also it configures > > dp/dm interrupts accordingly to support wakeup from system suspend. > > > > More info regarding the same can be found at: > > commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") > > commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") > > > > In the event, dwc3 probe gets deferred and is processed after dwc3-qcom > > probe, driver ends up reading the wakeup capability of dwc3 core as false > > leading to instability in suspend/resume path. > > > > To avoid this scenario, ensure dwc3_probe is successful by checking > > if appropriate driver is assigned to it or not after the of_platform_populate > > call. If it isn't then defer dwc3-qcom probe as well. > > > > Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") > > Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> > > Reported-by: Matthias Kaehlcke <mka@chromium.org> > Tested-by: Matthias Kaehlcke <mka@chromium.org> > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> (attempt to 'summarize' and move the discussion from v1 [1] to here) gregkh> Why not limit this check to a device type like your changelog mentions? mka> It is not an sc7180 specific issue. It can occur on any platform where the mka> dwc3 core has supplies that aren't ready when the dwc3-qcom driver probes. mka> mka> It won't blow up right away since it requires 'wakeup-source' to be set for mka> the dwc3 core, which currently is only the case for 'usb@a600000' of the mka> sc7280 AFAIK (I set it for sc7180 in my tree for testing, which is when I mka> found the issue this patch intends to address). krishna> As Mathias pointed out, no issue was seen so far on present QC targets krishna> as wakeup-source property was added recently and only for SC7180 and krishna> SC7280. We ran into some issues like wakeup from system suspend in krishna> host mode wasn't happening although we enabled wakeup-source in SC7180 krishna> that eventually led us to this bug. But, we tried to add debug prints krishna> to follow the code flow and see that the issue is present on SM8350 krishna> as well : "supplier 88e9000.phy-wrapper not ready" and deferring dwc3 krishna> probe. This doesn't seem to be specific to SC7180. krishna> krishna> Since this is seen on multiple platforms, can we go ahead without krishna> having any platforms specific checks in the code as in V2 version ? [1] https://lore.kernel.org/all/YtAv1U1VYkhIY1GA@kroah.com/t/#m6714bf1f2309cfe8be92e6c270ef2a99a9b09ac6
On Fri, Jul 15, 2022 at 06:51:52PM +0530, Krishna Kurapati wrote: > On SC7180 devices, it is observed that dwc3 probing is deferred > because device_links_check_suppliers() finds that '88e3000.phy' > isn't ready yet. > > As a part of its probe call, dwc3-qcom driver checks if dwc3 core > is wakeup capable or not. If the dwc3 core is wakeup capable, driver > configures dwc-qcom's power domain to be always ON. Also it configures > dp/dm interrupts accordingly to support wakeup from system suspend. > > More info regarding the same can be found at: > commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") > commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") > > In the event, dwc3 probe gets deferred and is processed after dwc3-qcom > probe, driver ends up reading the wakeup capability of dwc3 core as false > leading to instability in suspend/resume path. > > To avoid this scenario, ensure dwc3_probe is successful by checking > if appropriate driver is assigned to it or not after the of_platform_populate > call. If it isn't then defer dwc3-qcom probe as well. > > Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") > Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> > --- > v2: Set return value to EPROBE_DEFER to drop reference to dwc3 node > > drivers/usb/dwc3/dwc3-qcom.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c > index 7703655..6676b39 100644 > --- a/drivers/usb/dwc3/dwc3-qcom.c > +++ b/drivers/usb/dwc3/dwc3-qcom.c > @@ -722,6 +722,9 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev) > dev_err(dev, "failed to get dwc3 platform device\n"); > } > > + if (!qcom->dwc3->dev.driver) > + ret = -EPROBE_DEFER; > + > node_put: > of_node_put(dwc3_np); NAK. We should not be adding hacks like this to the driver. There are other ways to avoid this, but please take a look at the following series which makes the problem identified by this patch go away first: https://lore.kernel.org/all/20220802151404.1797-1-johan+linaro@kernel.org Johan
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c index 7703655..6676b39 100644 --- a/drivers/usb/dwc3/dwc3-qcom.c +++ b/drivers/usb/dwc3/dwc3-qcom.c @@ -722,6 +722,9 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev) dev_err(dev, "failed to get dwc3 platform device\n"); } + if (!qcom->dwc3->dev.driver) + ret = -EPROBE_DEFER; + node_put: of_node_put(dwc3_np);
On SC7180 devices, it is observed that dwc3 probing is deferred because device_links_check_suppliers() finds that '88e3000.phy' isn't ready yet. As a part of its probe call, dwc3-qcom driver checks if dwc3 core is wakeup capable or not. If the dwc3 core is wakeup capable, driver configures dwc-qcom's power domain to be always ON. Also it configures dp/dm interrupts accordingly to support wakeup from system suspend. More info regarding the same can be found at: commit d9be8d5c5b03 ("usb: dwc3: qcom: Keep power domain on to retain controller status") commit 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend") In the event, dwc3 probe gets deferred and is processed after dwc3-qcom probe, driver ends up reading the wakeup capability of dwc3 core as false leading to instability in suspend/resume path. To avoid this scenario, ensure dwc3_probe is successful by checking if appropriate driver is assigned to it or not after the of_platform_populate call. If it isn't then defer dwc3-qcom probe as well. Fixes: 649f5c842ba3 ("usb: dwc3: core: Host wake up support from system suspend") Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com> --- v2: Set return value to EPROBE_DEFER to drop reference to dwc3 node drivers/usb/dwc3/dwc3-qcom.c | 3 +++ 1 file changed, 3 insertions(+)