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Message-ID: <YlbyptYB/VFUDF0Q@google.com>
Date: Wed, 13 Apr 2022 08:56:22 -0700
From: Matthias Kaehlcke <mka@...omium.org>
To: "Sandeep Maheswaram (Temp)" <quic_c_sanm@...cinc.com>
Cc: Pavan Kondeti <quic_pkondeti@...cinc.com>,
Rob Herring <robh+dt@...nel.org>,
Andy Gross <agross@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Felipe Balbi <balbi@...nel.org>,
Stephen Boyd <swboyd@...omium.org>,
Doug Anderson <dianders@...omium.org>,
Mathias Nyman <mathias.nyman@...el.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
quic_ppratap@...cinc.com, quic_kriskura@...cinc.com,
quic_vpulyala@...cinc.com
Subject: Re: [PATCH v13 2/6] usb: dwc3: core: Host wake up support from
system suspend
On Wed, Apr 13, 2022 at 02:38:33PM +0530, Sandeep Maheswaram (Temp) wrote:
> Hi Matthias,
>
> On 4/13/2022 12:35 AM, Matthias Kaehlcke wrote:
> > On Tue, Apr 12, 2022 at 12:08:02PM +0530, Sandeep Maheswaram (Temp) wrote:
> > > Hi Pavan,
> > >
> > > On 4/12/2022 10:30 AM, Pavan Kondeti wrote:
> > > > Hi Sandeep,
> > > >
> > > > On Tue, Apr 12, 2022 at 10:16:39AM +0530, Sandeep Maheswaram (Temp) wrote:
> > > > > Hi Matthias,
> > > > >
> > > > > On 4/12/2022 2:24 AM, Matthias Kaehlcke wrote:
> > > > > > On Tue, Apr 12, 2022 at 12:46:50AM +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 wakep-source property for dwc3 core node to set the
> > > > > > s/wakep/wakeup/
> > > > > Okay. Will update in next version.
> > > > > > > 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@...cinc.com>
> > > > > > > ---
> > > > > > A per-patch change log would be really helpful for reviewers, even
> > > > > > if it doesn't include older versions.
> > > > > Okay. Will update in next version.
> > > > > > > drivers/usb/dwc3/core.c | 33 ++++++++++++++++++++-------------
> > > > > > > drivers/usb/dwc3/core.h | 4 ++++
> > > > > > > drivers/usb/dwc3/host.c | 25 +++++++++++++++++++++++++
> > > > > > > 3 files changed, 49 insertions(+), 13 deletions(-)
> > > > > > >
> > > > > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > > > > > > index 1170b80..effaa43 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) &&
> > > > > > > + usb_wakeup_enabled_descendants(hcd->self.root_hub)) {
> > > > > > You did not answer my question on v12, reposting it:
> > > > > >
> > > > > > Did you ever try whether you could use device_children_wakeup_capable() from
> > > > > > [1] instead of usb_wakeup_enabled_descendants()?
> > > > > >
> > > > > > [1] https://patchwork.kernel.org/project/linux-usb/patch/1635753224-23975-2-git-send-email-quic_c_sanm@quicinc.com/#24566065
> > > > > Sorry ..I have replied in mail yesterday but it is not showing up in
> > > > > patchwork link.
> > > > >
> > > > > Tried with device_children_wakeup_capable(dwc->dev) instead of
> > > > > usb_wakeup_enabled_descendants and it always returns true even
> > > > >
> > > > > when no devices are connected.
> > > > >
> > > > What do you mean by when no devices are connected? There is always
> > > > root hub connected and we should not power down the DWC3 here even
> > > > when remote wakeup for root hub is enabled. Essentially
> > > > usb_wakeup_enabled_descendants() returns true even without any
> > > > physical devices connected.
> > > >
> > > > What does device_children_wakeup_capable() do? Sorry, I could not
> > > > find this function definition.
> > > >
> > > > Thanks,
> > > > Pavan
> > > usb_wakeup_enabled_descendants() doesn't consider hubs. It only returns true if any devices
> > > are connected with wakeup capability apart from hubs.
> > Actually it considers hubs:
> >
> > unsigned usb_wakeup_enabled_descendants(struct usb_device *udev)
> > {
> > struct usb_hub *hub = usb_hub_to_struct_hub(udev);
> >
> > return udev->do_remote_wakeup +
> > (hub ? hub->wakeup_enabled_descendants : 0);
> > }
> >
> > 'udev' may or may not be a hub, if 'do_remote_wakeup' is set then the
> > device is considered a wakeup enabled descendant.
> >
> > And for system suspebd 'do_remote_wakeup' is set based on the wakeup
> > config of the device:
> >
> > static void choose_wakeup(struct usb_device *udev, pm_message_t msg)
> > {
> > ...
> > w = device_may_wakeup(&udev->dev);
> > ...
> > udev->do_remote_wakeup = w;
> > }
> >
> > I checked on three systems with different Linux distributions, on all of
> > the wakeup flag of a connected hub is 'disabled'. Wakeup still works, so
> > apparently that flag doesn't really have an impact for child ports.
> >
> > > If we consider hubs also dwc3 core exit and phy exit will never be called.
> > >
> > > device_children_wakeup_capable() implementation was shared by Matthias in below thread
> > > https://patchwork.kernel.org/project/linux-usb/patch/1635753224-23975-2-git-send-email-quic_c_sanm@quicinc.com/#24566065
> > >
> > > Probably device_children_wakeup_capable() is returning true because it considers hubs also.
> > I thought I did a basic test when I sent the patch, I did another (?) one
> > with v13 of your patch set. In this tests with a hub connected the
> > function returns true when an HID device is connected, and false when
> > nothing is connected. The wakeup flag of the hub is disabled (default).
> >
> > Sandeep, are the wakeup flags of the child hub(s) set to 'enabled' on
> > the system you tested on?
>
> The wakeup flags of hub is 'disabled' on system I tested.
>
> What is the input param you are giving to device_children_wakeup_capable() function ?
I passed '&hcd->self.root_hub->dev'
> I was passing the dwc->dev like this device_children_wakeup_capable(dwc->dev) .Is it right?
The DWC doesn't know anything about the connected USB devices, so this only
checks wakeup capability/policy of the DWC itself.
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