Re: [PATCH 0/5] usb: dwc3: qcom: Allow runtime PM

Manivannan Sadhasivam
2023-03-27T09:17:51Z

On Mon, Mar 27, 2023 at 11:01:35AM +0200, Konrad Dybcio wrote:
>
>
> On 25.03.2023 17:52, Manivannan Sadhasivam wrote:
> > Hi,
> >
> > This series allows the dwc3-qcom driver to do runtime PM itself without
> > userspace intervention. Still, userspace is required to enable runtime PM
> > for dwc3 glue and xhci drivers as we cannot enable runtime PM for them.
> > But this series avoids one more additional step.
> What sort of 'userspace intervention' are we talking about?
> echo mem > /sys/power/state?
>

I forgot to add that bit:

echo auto > /sys/devices/platform/soc@0/a8f8800.usb/a800000.usb/xhci-hcd.1.auto/power/control
echo auto > /sys/devices/platform/soc@0/a8f8800.usb/a800000.usb/power/control

You need to set "auto" for the runtime control for both xhci and dwc drivers.

Then if you don't connect a usb device, all 3 drivers (dwc3-qcom, dwc3, and
xhci) will become runtime suspended after a delay of 5s (default delay).

This can be confirmed by:

cat /sys/devices/platform/soc@0/a8f8800.usb/power/runtime_status

After connecting a usb device, they will all become "active".

Thanks,
Mani

> Konrad
> >
> > While enabling runtime PM, I noticed that the xhci driver suspends before
> > catching the xhci interrupts during resume. This ended up deferring the
> > device enumeration for some time. So I included a patch adding autosuspend
> > delay of 200ms to the xhci driver. With this delay, usb enumeration happens
> > properly.
> >
> > This series has been tested on SC8280XP-CRD and RB5 devices.
> >
> > Thanks,
> > Mani
> >
> > Manivannan Sadhasivam (5):
> > arm64: dts: qcom: sc8280xp: Add missing dwc3 quirks
> > xhci: host: Use 200ms autosuspend delay for runtime suspend
> > usb: dwc3: qcom: Fix null ptr access during runtime_suspend()
> > usb: dwc3: qcom: Clear pending interrupt before enabling wake
> > interrupt
> > usb: dwc3: qcom: Allow runtime PM
> >
> > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 14 ++++++++++++++
> > drivers/usb/dwc3/dwc3-qcom.c | 13 +++++++++----
> > drivers/usb/host/xhci-plat.c | 2 ++
> > 3 files changed, 25 insertions(+), 4 deletions(-)
> >

--
மணிவண்ணன் சதாசிவம்