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Message-ID: <20220412064920.GD2627@hu-pkondeti-hyd.qualcomm.com>
Date: Tue, 12 Apr 2022 12:19:20 +0530
From: Pavan Kondeti <quic_pkondeti@...cinc.com>
To: "Sandeep Maheswaram (Temp)" <quic_c_sanm@...cinc.com>
CC: Pavan Kondeti <quic_pkondeti@...cinc.com>,
Matthias Kaehlcke <mka@...omium.org>,
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
Hi Sandeep,
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. If we consider hubs also dwc3 core exit
> and phy exit will never be called.
>
copy/pasting the code here. you are passing roothub as udev. As you can see
this function clearly takes the remote wakeup of root hub into account. Lets
take a simple case, we have a roothub with one port. nothing attached. so
we enter runtime suspend. Don't you want to keep PHY ON? otherwise, how can
you detect if a keyboard/mouse attached directly to root hub?
In your configuration, is remote wakeup enabled for the roothub or not?
/* Count of wakeup-enabled devices at or below udev */
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);
}
> 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.
>
if you see choose_wakeup(), it derives the USB remote wakeup capability from
the device_may_wakeup(), so the patch suggested might work. Note that we have
to take wakeup capability of roothub into account even when there is no
USB device attached.
Thanks,
Pavan
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