Re: [PATCH] drm/msm/dp: Shorten SETUP timeout

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On 2021-10-07 15:34, Stephen Boyd wrote:
Quoting khsieh@xxxxxxxxxxxxxx (2021-10-07 13:28:12)
On 2021-10-07 13:06, Bjorn Andersson wrote:
> On Thu 07 Oct 12:51 PDT 2021, khsieh@xxxxxxxxxxxxxx wrote:
>
>> On 2021-10-06 10:31, Bjorn Andersson wrote:
>> > On Wed 06 Oct 08:37 PDT 2021, khsieh@xxxxxxxxxxxxxx wrote:
>> >
>> > > On 2021-10-05 19:10, Bjorn Andersson wrote:
>> > > > On Tue 05 Oct 16:04 PDT 2021, khsieh@xxxxxxxxxxxxxx wrote:
>> > > >
>> > > > > On 2021-10-05 15:36, Stephen Boyd wrote:
>> > > > > > Quoting Bjorn Andersson (2021-10-05 14:40:38)
>> > > > > > > On Tue 05 Oct 11:45 PDT 2021, Stephen Boyd wrote:
>> > > > > > >
>> > > > > > > > Quoting Bjorn Andersson (2021-10-04 19:37:50)
>> > > > > > > > > Found in the middle of a patch from Sankeerth was the reduction of the
>> > > > > > > > > INIT_SETUP timeout from 10s to 100ms. Upon INIT_SETUP timeout the host
>> > > > > > > > > is initalized and HPD interrupt start to be serviced, so in the case of
>> > > > > > > > > eDP this reduction improves the user experience dramatically - i.e.
>> > > > > > > > > removes 9.9s of bland screen time at boot.
>> > > > > > > > >
>> > > > > > > > > Suggested-by: Sankeerth Billakanti <sbillaka@xxxxxxxxxxxxxx>
>> > > > > > > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
>> > > > > > > > > ---
>> > > > > > > >
>> > > > > > > > Any Fixes tag? BTW, the delay design is pretty convoluted. I had to go
>> > > > > > > > re-read the code a couple times to understand that it's waiting 100ms
>> > > > > > > > times the 'delay' number. Whaaaaat?
>> > > > > > > >
>> > > > > > >
>> > > > > > > I assume you're happy with the current 10s delay on the current
>> > > > > > > devices, so I don't think we should push for this to be backported.
>> > > > > > > I have no need for it to be backported on my side at least.
>> > > > > > >
>> > > > > >
>> > > > > > Sure. Fixes tag != backported to stable trees but it is close.
>> > > > > >
>> > > > > > > > Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
>> > > > > > >
>> > > > >   dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 1); <== to 100ms
>> > > > >
>> > > > > This patch will prevent usb3 from working due to dp driver
>> > > > > initialize phy
>> > > > > earlier than usb3 which cause timeout error at power up usb3 phy
>> > > > > when both
>> > > > > edp and dp are enabled.
>> > > >
>> > > > Can you please help me understand what you mean here, I use this on my
>> > > > sc8180x with both eDP and USB-C/DP right now. What is it that doesn't
>> > > > work? Or am I just lucky in some race condition?
>> > > >
>> > > > Thanks,
>> > > > Bjorn
>> > > >
>> > > The problem is seen at sc7280.
>> > > Apple dongle have both  hdmi and usb port.
>> > > plug Apple dongle into type-c, then plug DP into apple's hdmi port
>> > > and usb
>> > > mouse into apple's usb port.
>> > > If edp enabled at this time, then usb mouse will not work due to
>> > > timeout at
>> > > phy power up.
>> > >
>> >
>> > Okay, so you're saying that if the DP driver invokes phy_power_on()
>> > before the USB driver does, USB initialization fails (or at least USB
>> > doesn't work)?
>>
>> if dp driver call qcom_qmp_phy_init() before usb3 call
>> qcom_qmp_phy_init(),
>> usb3 driver will timeout at readl_poll_timeout(status, val, (val &
>> mask) ==
>> ready, 10, PHY_INIT_COMPLETE_TIMEOUT) of qcom_qmp_phy_power_on().
>
> Thanks, I will try to reproduce this on my side. So the 10 seconds here
> is strictly to give good enough time for the dwc3 driver to probe...
>
> Any idea why you're saying that this is specific to sc7280, what
> changed
> from sc7180?

I did not have sc7180 with edp before so that i am not sure it will
happen on sc7180 or not.
The usb3 does not work when both edp and dp enabled I just seen at
sc7280.
Current at sc7280 EC is not boot up correctly when system power up.
I have to manual reboot EC from linux kernel shell before DP/usb3 can
work.
I am not sure this contribute to this problem or not.


Can you make the usb driver into a module and only load that module
later in boot after the DP driver calls qcom_qmp_phy_init()? That would
be an easy way to move usb probe after DP probe and expose this problem.

we need usb calls qcom_qmp_phy_init() before dp.



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