| Message ID | 1650395470-31333-1-git-send-email-quic_c_sanm@quicinc.com |
|---|---|
| Headers | show |
| Series | USB DWC3 host wake up support from system suspend | expand |
On Wed, Apr 20, 2022 at 12:41:06AM +0530, Sandeep Maheswaram wrote: > During suspend read the status of all port and set hs phy mode > based on current speed. Use this hs phy mode to configure wakeup > interrupts in qcom glue driver. > > Check wakeup-source property for dwc3 core node to set the > wakeup capability. Drop the device_init_wakeup call from > runtime suspend and resume. > > Also check during suspend if any wakeup capable devices are > connected to the controller (directly or through hubs), if there > are none set a flag to indicate that the PHY is powered > down during suspend. > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com> > --- > v14: > Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants. > > v13: > Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode. > Removed device_init_wakeup calls from dwc3_runtime_suspend and dwc3_runtime_resume > as we have a new dt property wakeup-source. > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++------------- > drivers/usb/dwc3/core.h | 4 ++++ > drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++ > 3 files changed, 48 insertions(+), 13 deletions(-) > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > index 1170b80..898aa66 100644 > --- a/drivers/usb/dwc3/core.c > +++ b/drivers/usb/dwc3/core.c > @@ -32,6 +32,7 @@ > #include <linux/usb/gadget.h> > #include <linux/usb/of.h> > #include <linux/usb/otg.h> > +#include <linux/usb/hcd.h> > > #include "core.h" > #include "gadget.h" > @@ -1723,6 +1724,7 @@ static int dwc3_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, dwc); > dwc3_cache_hwparams(dwc); > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source")); > > spin_lock_init(&dwc->lock); > mutex_init(&dwc->mutex); > @@ -1865,6 +1867,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > { > unsigned long flags; > u32 reg; > + struct usb_hcd *hcd = platform_get_drvdata(dwc->xhci); > > switch (dwc->current_dr_role) { > case DWC3_GCTL_PRTCAP_DEVICE: > @@ -1877,10 +1880,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > dwc3_core_exit(dwc); > break; > case DWC3_GCTL_PRTCAP_HOST: > - if (!PMSG_IS_AUTO(msg)) { > - dwc3_core_exit(dwc); > - break; > - } > + dwc3_check_phy_speed_mode(dwc); > > /* Let controller to suspend HSPHY before PHY driver suspends */ > if (dwc->dis_u2_susphy_quirk || > @@ -1896,6 +1896,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > phy_pm_runtime_put_sync(dwc->usb2_generic_phy); > phy_pm_runtime_put_sync(dwc->usb3_generic_phy); > + > + if (!PMSG_IS_AUTO(msg)) { > + if (device_may_wakeup(dwc->dev) && > + device_children_wakeup_capable(&hcd->self.root_hub->dev)) { > + dwc->phy_power_off = false; > + } else { > + dwc->phy_power_off = true; > + dwc3_core_exit(dwc); I found that shutting the PHYs down during suspend leads to high power consumption of a downstream hub (about 80mW vs 15mW when the PHYs are not shut down). It would be interesting to know if this also impacts other non-hub peripherals. Unfortunately I can't test that, the hub on my system is soldered to the board. I understand that shutting the PHYs down might be beneficial in terms of power on some systems, however on those I'm looking at we'd strongly prefer to save the 65mW of power consumed by the hub, rather than whatever smaller amount of power that is saved by powering down the PHYs. Could we introduce a sysfs attribute (or some other sort of knob) to allow the admin to configure whether the PHYs should remain on or off during suspend? That is assuming that it is actually desirable to power them off on some systems.
On Wed, May 04, 2022 at 10:46:30AM -0700, Matthias Kaehlcke wrote: > On Wed, Apr 20, 2022 at 12:41:06AM +0530, Sandeep Maheswaram wrote: > > During suspend read the status of all port and set hs phy mode > > based on current speed. Use this hs phy mode to configure wakeup > > interrupts in qcom glue driver. > > > > Check wakeup-source property for dwc3 core node to set the > > wakeup capability. Drop the device_init_wakeup call from > > runtime suspend and resume. > > > > Also check during suspend if any wakeup capable devices are > > connected to the controller (directly or through hubs), if there > > are none set a flag to indicate that the PHY is powered > > down during suspend. > > > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com> > > --- > > v14: > > Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants. > > > > v13: > > Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode. > > Removed device_init_wakeup calls from dwc3_runtime_suspend and dwc3_runtime_resume > > as we have a new dt property wakeup-source. > > > > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++------------- > > drivers/usb/dwc3/core.h | 4 ++++ > > drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++ > > 3 files changed, 48 insertions(+), 13 deletions(-) > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > index 1170b80..898aa66 100644 > > --- a/drivers/usb/dwc3/core.c > > +++ b/drivers/usb/dwc3/core.c > > @@ -32,6 +32,7 @@ > > #include <linux/usb/gadget.h> > > #include <linux/usb/of.h> > > #include <linux/usb/otg.h> > > +#include <linux/usb/hcd.h> > > > > #include "core.h" > > #include "gadget.h" > > @@ -1723,6 +1724,7 @@ static int dwc3_probe(struct platform_device *pdev) > > > > platform_set_drvdata(pdev, dwc); > > dwc3_cache_hwparams(dwc); > > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source")); > > > > spin_lock_init(&dwc->lock); > > mutex_init(&dwc->mutex); > > @@ -1865,6 +1867,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > { > > unsigned long flags; > > u32 reg; > > + struct usb_hcd *hcd = platform_get_drvdata(dwc->xhci); > > > > switch (dwc->current_dr_role) { > > case DWC3_GCTL_PRTCAP_DEVICE: > > @@ -1877,10 +1880,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > dwc3_core_exit(dwc); > > break; > > case DWC3_GCTL_PRTCAP_HOST: > > - if (!PMSG_IS_AUTO(msg)) { > > - dwc3_core_exit(dwc); > > - break; > > - } > > + dwc3_check_phy_speed_mode(dwc); > > > > /* Let controller to suspend HSPHY before PHY driver suspends */ > > if (dwc->dis_u2_susphy_quirk || > > @@ -1896,6 +1896,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > phy_pm_runtime_put_sync(dwc->usb2_generic_phy); > > phy_pm_runtime_put_sync(dwc->usb3_generic_phy); > > + > > + if (!PMSG_IS_AUTO(msg)) { > > + if (device_may_wakeup(dwc->dev) && > > + device_children_wakeup_capable(&hcd->self.root_hub->dev)) { > > + dwc->phy_power_off = false; > > + } else { > > + dwc->phy_power_off = true; > > + dwc3_core_exit(dwc); > > I found that shutting the PHYs down during suspend leads to high power > consumption of a downstream hub (about 80mW vs 15mW when the PHYs are > not shut down). > > It would be interesting to know if this also impacts other non-hub > peripherals. Unfortunately I can't test that, the hub on my system is > soldered to the board. > > I understand that shutting the PHYs down might be beneficial in terms > of power on some systems, however on those I'm looking at we'd strongly > prefer to save the 65mW of power consumed by the hub, rather than > whatever smaller amount of power that is saved by powering down the > PHYs. > > Could we introduce a sysfs attribute (or some other sort of knob) to > allow the admin to configure whether the PHYs should remain on or off > during suspend? That is assuming that it is actually desirable to power > them off on some systems. The result may vary across SoCs also. The current proposal is to keep PHY powered during system suspend if any of the downstream USB devices are enabled for wakeup. This also includes USB2/USB3 root hub. If one wants to keep PHY always powered on even when no device is attached, they can do so by enabling wakeup (echo enabled > /sys/bus/usb/devices/usbX/power/wakeup). This is anyway needed if you want to detect a peripheral attach during system suspend. Thanks, Pavan
On Thu, May 05, 2022 at 08:56:18AM +0530, Pavan Kondeti wrote: > On Wed, May 04, 2022 at 10:46:30AM -0700, Matthias Kaehlcke wrote: > > On Wed, Apr 20, 2022 at 12:41:06AM +0530, Sandeep Maheswaram wrote: > > > During suspend read the status of all port and set hs phy mode > > > based on current speed. Use this hs phy mode to configure wakeup > > > interrupts in qcom glue driver. > > > > > > Check wakeup-source property for dwc3 core node to set the > > > wakeup capability. Drop the device_init_wakeup call from > > > runtime suspend and resume. > > > > > > Also check during suspend if any wakeup capable devices are > > > connected to the controller (directly or through hubs), if there > > > are none set a flag to indicate that the PHY is powered > > > down during suspend. > > > > > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com> > > > --- > > > v14: > > > Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants. > > > > > > v13: > > > Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode. > > > Removed device_init_wakeup calls from dwc3_runtime_suspend and dwc3_runtime_resume > > > as we have a new dt property wakeup-source. > > > > > > > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++------------- > > > drivers/usb/dwc3/core.h | 4 ++++ > > > drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++ > > > 3 files changed, 48 insertions(+), 13 deletions(-) > > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > > index 1170b80..898aa66 100644 > > > --- a/drivers/usb/dwc3/core.c > > > +++ b/drivers/usb/dwc3/core.c > > > @@ -32,6 +32,7 @@ > > > #include <linux/usb/gadget.h> > > > #include <linux/usb/of.h> > > > #include <linux/usb/otg.h> > > > +#include <linux/usb/hcd.h> > > > > > > #include "core.h" > > > #include "gadget.h" > > > @@ -1723,6 +1724,7 @@ static int dwc3_probe(struct platform_device *pdev) > > > > > > platform_set_drvdata(pdev, dwc); > > > dwc3_cache_hwparams(dwc); > > > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source")); > > > > > > spin_lock_init(&dwc->lock); > > > mutex_init(&dwc->mutex); > > > @@ -1865,6 +1867,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > { > > > unsigned long flags; > > > u32 reg; > > > + struct usb_hcd *hcd = platform_get_drvdata(dwc->xhci); > > > > > > switch (dwc->current_dr_role) { > > > case DWC3_GCTL_PRTCAP_DEVICE: > > > @@ -1877,10 +1880,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > dwc3_core_exit(dwc); > > > break; > > > case DWC3_GCTL_PRTCAP_HOST: > > > - if (!PMSG_IS_AUTO(msg)) { > > > - dwc3_core_exit(dwc); > > > - break; > > > - } > > > + dwc3_check_phy_speed_mode(dwc); > > > > > > /* Let controller to suspend HSPHY before PHY driver suspends */ > > > if (dwc->dis_u2_susphy_quirk || > > > @@ -1896,6 +1896,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > > > phy_pm_runtime_put_sync(dwc->usb2_generic_phy); > > > phy_pm_runtime_put_sync(dwc->usb3_generic_phy); > > > + > > > + if (!PMSG_IS_AUTO(msg)) { > > > + if (device_may_wakeup(dwc->dev) && > > > + device_children_wakeup_capable(&hcd->self.root_hub->dev)) { > > > + dwc->phy_power_off = false; > > > + } else { > > > + dwc->phy_power_off = true; > > > + dwc3_core_exit(dwc); > > > > I found that shutting the PHYs down during suspend leads to high power > > consumption of a downstream hub (about 80mW vs 15mW when the PHYs are > > not shut down). > > > > It would be interesting to know if this also impacts other non-hub > > peripherals. Unfortunately I can't test that, the hub on my system is > > soldered to the board. > > > > I understand that shutting the PHYs down might be beneficial in terms > > of power on some systems, however on those I'm looking at we'd strongly > > prefer to save the 65mW of power consumed by the hub, rather than > > whatever smaller amount of power that is saved by powering down the > > PHYs. > > > > Could we introduce a sysfs attribute (or some other sort of knob) to > > allow the admin to configure whether the PHYs should remain on or off > > during suspend? That is assuming that it is actually desirable to power > > them off on some systems. > > The result may vary across SoCs also. The current proposal is to keep PHY > powered during system suspend if any of the downstream USB devices are enabled > for wakeup. This also includes USB2/USB3 root hub. If one wants to keep PHY > always powered on even when no device is attached, they can do so by enabling > wakeup (echo enabled > /sys/bus/usb/devices/usbX/power/wakeup). This is anyway > needed if you want to detect a peripheral attach during system suspend. My concern is that it is not evident for an admin what causes the high power consumption of the USB client (if they detect/localize it in the first place), and even less that wakeup needs to be enabled to mitigate it. Why can't we just put the PHYs in suspend, rather than taking the controller down completely during suspend?
On Thu, May 05, 2022 at 09:45:49AM -0700, Matthias Kaehlcke wrote: > On Thu, May 05, 2022 at 08:56:18AM +0530, Pavan Kondeti wrote: > > On Wed, May 04, 2022 at 10:46:30AM -0700, Matthias Kaehlcke wrote: > > > On Wed, Apr 20, 2022 at 12:41:06AM +0530, Sandeep Maheswaram wrote: > > > > During suspend read the status of all port and set hs phy mode > > > > based on current speed. Use this hs phy mode to configure wakeup > > > > interrupts in qcom glue driver. > > > > > > > > Check wakeup-source property for dwc3 core node to set the > > > > wakeup capability. Drop the device_init_wakeup call from > > > > runtime suspend and resume. > > > > > > > > Also check during suspend if any wakeup capable devices are > > > > connected to the controller (directly or through hubs), if there > > > > are none set a flag to indicate that the PHY is powered > > > > down during suspend. > > > > > > > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com> > > > > --- > > > > v14: > > > > Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants. > > > > > > > > v13: > > > > Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode. > > > > Removed device_init_wakeup calls from dwc3_runtime_suspend and dwc3_runtime_resume > > > > as we have a new dt property wakeup-source. > > > > > > > > > > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++------------- > > > > drivers/usb/dwc3/core.h | 4 ++++ > > > > drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++ > > > > 3 files changed, 48 insertions(+), 13 deletions(-) > > > > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > > > index 1170b80..898aa66 100644 > > > > --- a/drivers/usb/dwc3/core.c > > > > +++ b/drivers/usb/dwc3/core.c > > > > @@ -32,6 +32,7 @@ > > > > #include <linux/usb/gadget.h> > > > > #include <linux/usb/of.h> > > > > #include <linux/usb/otg.h> > > > > +#include <linux/usb/hcd.h> > > > > > > > > #include "core.h" > > > > #include "gadget.h" > > > > @@ -1723,6 +1724,7 @@ static int dwc3_probe(struct platform_device *pdev) > > > > > > > > platform_set_drvdata(pdev, dwc); > > > > dwc3_cache_hwparams(dwc); > > > > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source")); > > > > > > > > spin_lock_init(&dwc->lock); > > > > mutex_init(&dwc->mutex); > > > > @@ -1865,6 +1867,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > { > > > > unsigned long flags; > > > > u32 reg; > > > > + struct usb_hcd *hcd = platform_get_drvdata(dwc->xhci); > > > > > > > > switch (dwc->current_dr_role) { > > > > case DWC3_GCTL_PRTCAP_DEVICE: > > > > @@ -1877,10 +1880,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > dwc3_core_exit(dwc); > > > > break; > > > > case DWC3_GCTL_PRTCAP_HOST: > > > > - if (!PMSG_IS_AUTO(msg)) { > > > > - dwc3_core_exit(dwc); > > > > - break; > > > > - } > > > > + dwc3_check_phy_speed_mode(dwc); > > > > > > > > /* Let controller to suspend HSPHY before PHY driver suspends */ > > > > if (dwc->dis_u2_susphy_quirk || > > > > @@ -1896,6 +1896,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > > > > > phy_pm_runtime_put_sync(dwc->usb2_generic_phy); > > > > phy_pm_runtime_put_sync(dwc->usb3_generic_phy); > > > > + > > > > + if (!PMSG_IS_AUTO(msg)) { > > > > + if (device_may_wakeup(dwc->dev) && > > > > + device_children_wakeup_capable(&hcd->self.root_hub->dev)) { > > > > + dwc->phy_power_off = false; > > > > + } else { > > > > + dwc->phy_power_off = true; > > > > + dwc3_core_exit(dwc); > > > > > > I found that shutting the PHYs down during suspend leads to high power > > > consumption of a downstream hub (about 80mW vs 15mW when the PHYs are > > > not shut down). > > > > > > It would be interesting to know if this also impacts other non-hub > > > peripherals. Unfortunately I can't test that, the hub on my system is > > > soldered to the board. > > > > > > I understand that shutting the PHYs down might be beneficial in terms > > > of power on some systems, however on those I'm looking at we'd strongly > > > prefer to save the 65mW of power consumed by the hub, rather than > > > whatever smaller amount of power that is saved by powering down the > > > PHYs. > > > > > > Could we introduce a sysfs attribute (or some other sort of knob) to > > > allow the admin to configure whether the PHYs should remain on or off > > > during suspend? That is assuming that it is actually desirable to power > > > them off on some systems. > > > > The result may vary across SoCs also. The current proposal is to keep PHY > > powered during system suspend if any of the downstream USB devices are enabled > > for wakeup. This also includes USB2/USB3 root hub. If one wants to keep PHY > > always powered on even when no device is attached, they can do so by enabling > > wakeup (echo enabled > /sys/bus/usb/devices/usbX/power/wakeup). This is anyway > > needed if you want to detect a peripheral attach during system suspend. > > My concern is that it is not evident for an admin what causes the high power > consumption of the USB client (if they detect/localize it in the first place), > and even less that wakeup needs to be enabled to mitigate it. > > Why can't we just put the PHYs in suspend, rather than taking the controller > down completely during suspend? Agreed and I also have the same question. I don't know the background on why DWC3 chooses to power down the PHY(s) during system suspend. Probably it is beneficial in some board designs. Atleast this patch series provides a way to wakeup the USB from system suspend, which also can be used not to power down the PHY(s). If all the users of DWC3 agree that powering down the PHY is bad, then we can do something about it. Thanks, Pavan
On Fri, May 06, 2022 at 08:31:07AM +0530, Pavan Kondeti wrote: > On Thu, May 05, 2022 at 09:45:49AM -0700, Matthias Kaehlcke wrote: > > On Thu, May 05, 2022 at 08:56:18AM +0530, Pavan Kondeti wrote: > > > On Wed, May 04, 2022 at 10:46:30AM -0700, Matthias Kaehlcke wrote: > > > > On Wed, Apr 20, 2022 at 12:41:06AM +0530, Sandeep Maheswaram wrote: > > > > > During suspend read the status of all port and set hs phy mode > > > > > based on current speed. Use this hs phy mode to configure wakeup > > > > > interrupts in qcom glue driver. > > > > > > > > > > Check wakeup-source property for dwc3 core node to set the > > > > > wakeup capability. Drop the device_init_wakeup call from > > > > > runtime suspend and resume. > > > > > > > > > > Also check during suspend if any wakeup capable devices are > > > > > connected to the controller (directly or through hubs), if there > > > > > are none set a flag to indicate that the PHY is powered > > > > > down during suspend. > > > > > > > > > > Signed-off-by: Sandeep Maheswaram <quic_c_sanm@quicinc.com> > > > > > --- > > > > > v14: > > > > > Used device_children_wakeup_capable instead of usb_wakeup_enabled_descendants. > > > > > > > > > > v13: > > > > > Changed dwc3_set_phy_speed_mode to dwc3_check_phy_speed_mode. > > > > > Removed device_init_wakeup calls from dwc3_runtime_suspend and dwc3_runtime_resume > > > > > as we have a new dt property wakeup-source. > > > > > > > > > > > > > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++------------- > > > > > drivers/usb/dwc3/core.h | 4 ++++ > > > > > drivers/usb/dwc3/host.c | 24 ++++++++++++++++++++++++ > > > > > 3 files changed, 48 insertions(+), 13 deletions(-) > > > > > > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c > > > > > index 1170b80..898aa66 100644 > > > > > --- a/drivers/usb/dwc3/core.c > > > > > +++ b/drivers/usb/dwc3/core.c > > > > > @@ -32,6 +32,7 @@ > > > > > #include <linux/usb/gadget.h> > > > > > #include <linux/usb/of.h> > > > > > #include <linux/usb/otg.h> > > > > > +#include <linux/usb/hcd.h> > > > > > > > > > > #include "core.h" > > > > > #include "gadget.h" > > > > > @@ -1723,6 +1724,7 @@ static int dwc3_probe(struct platform_device *pdev) > > > > > > > > > > platform_set_drvdata(pdev, dwc); > > > > > dwc3_cache_hwparams(dwc); > > > > > + device_init_wakeup(&pdev->dev, of_property_read_bool(dev->of_node, "wakeup-source")); > > > > > > > > > > spin_lock_init(&dwc->lock); > > > > > mutex_init(&dwc->mutex); > > > > > @@ -1865,6 +1867,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > > { > > > > > unsigned long flags; > > > > > u32 reg; > > > > > + struct usb_hcd *hcd = platform_get_drvdata(dwc->xhci); > > > > > > > > > > switch (dwc->current_dr_role) { > > > > > case DWC3_GCTL_PRTCAP_DEVICE: > > > > > @@ -1877,10 +1880,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > > dwc3_core_exit(dwc); > > > > > break; > > > > > case DWC3_GCTL_PRTCAP_HOST: > > > > > - if (!PMSG_IS_AUTO(msg)) { > > > > > - dwc3_core_exit(dwc); > > > > > - break; > > > > > - } > > > > > + dwc3_check_phy_speed_mode(dwc); > > > > > > > > > > /* Let controller to suspend HSPHY before PHY driver suspends */ > > > > > if (dwc->dis_u2_susphy_quirk || > > > > > @@ -1896,6 +1896,16 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg) > > > > > > > > > > phy_pm_runtime_put_sync(dwc->usb2_generic_phy); > > > > > phy_pm_runtime_put_sync(dwc->usb3_generic_phy); > > > > > + > > > > > + if (!PMSG_IS_AUTO(msg)) { > > > > > + if (device_may_wakeup(dwc->dev) && > > > > > + device_children_wakeup_capable(&hcd->self.root_hub->dev)) { > > > > > + dwc->phy_power_off = false; > > > > > + } else { > > > > > + dwc->phy_power_off = true; > > > > > + dwc3_core_exit(dwc); > > > > > > > > I found that shutting the PHYs down during suspend leads to high power > > > > consumption of a downstream hub (about 80mW vs 15mW when the PHYs are > > > > not shut down). > > > > > > > > It would be interesting to know if this also impacts other non-hub > > > > peripherals. Unfortunately I can't test that, the hub on my system is > > > > soldered to the board. > > > > > > > > I understand that shutting the PHYs down might be beneficial in terms > > > > of power on some systems, however on those I'm looking at we'd strongly > > > > prefer to save the 65mW of power consumed by the hub, rather than > > > > whatever smaller amount of power that is saved by powering down the > > > > PHYs. > > > > > > > > Could we introduce a sysfs attribute (or some other sort of knob) to > > > > allow the admin to configure whether the PHYs should remain on or off > > > > during suspend? That is assuming that it is actually desirable to power > > > > them off on some systems. > > > > > > The result may vary across SoCs also. The current proposal is to keep PHY > > > powered during system suspend if any of the downstream USB devices are enabled > > > for wakeup. This also includes USB2/USB3 root hub. If one wants to keep PHY > > > always powered on even when no device is attached, they can do so by enabling > > > wakeup (echo enabled > /sys/bus/usb/devices/usbX/power/wakeup). This is anyway > > > needed if you want to detect a peripheral attach during system suspend. > > > > My concern is that it is not evident for an admin what causes the high power > > consumption of the USB client (if they detect/localize it in the first place), > > and even less that wakeup needs to be enabled to mitigate it. > > > > Why can't we just put the PHYs in suspend, rather than taking the controller > > down completely during suspend? > > Agreed and I also have the same question. > > I don't know the background on why DWC3 chooses to power down the PHY(s) > during system suspend. Probably it is beneficial in some board designs. > Atleast this patch series provides a way to wakeup the USB from system > suspend, which also can be used not to power down the PHY(s). If all the users > of DWC3 agree that powering down the PHY is bad, then we can do something > about it. I came across this commit while doing a bit of archeology: commit c4a5153e87fdf6805f63ff57556260e2554155a5 Author: Manu Gautam <mgautam@codeaurora.org> Date: Thu Jan 18 16:54:30 2018 +0530 usb: dwc3: core: Power-off core/PHYs on system_suspend in host mode Commit 689bf72c6e0d ("usb: dwc3: Don't reinitialize core during host bus-suspend/resume") updated suspend/resume routines to not power_off and reinit PHYs/core for host mode. It broke platforms that rely on DWC3 core to power_off PHYs to enter low power state on system suspend. Perform dwc3_core_exit/init only during host mode system_suspend/ resume to addresses power regression from above mentioned patch and also allow USB session to stay connected across runtime_suspend/resume in host mode. While at it also replace existing checks for HOST only dr_mode with current_dr_role to have similar core driver behavior for both Host-only and DRD+Host configurations. Fixes: 689bf72c6e0d ("usb: dwc3: Don't reinitialize core during host bus-suspend/resume") Reviewed-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Manu Gautam <mgautam@codeaurora.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> So apparently powering off the core and PHYs is needed on some platforms. We could introduce a DT property that indicates that keeping the core/PHYs on is supported. Another hint could be the fact that the controller is marked as wakeup capable, however that would still power the core/PHYs down if the 'wakeup-source' property isn't set for a controller that is technically wakeup capable.