[PATCH] ath10k: Don't touch the CE interrupt registers after power up

[Yongqin Liu]

On Fri, 8 Dec 2023 at 00:49, Doug Anderson <dianders at chromium.org> wrote:
>
> Hi,
>
> On Thu, Dec 7, 2023 at 6:49 AM Kalle Valo <kvalo at kernel.org> wrote:
> >
> > > Recently during our Android build test on the Dragonboard 845c board,
> > > with the Android Common Kernel android11-5.4-lts and android12-5.4-lts branches,
> > >
> > > we found there are some ufshcd related changes printed,
> > > and the serial console gets stuck, no response for input,
> > > and the Android boot is stuck at the animation window.
> > >
> > > The problem is reported here
> > >     https://issuetracker.google.com/issues/314366682
> > > You could check there for more log details.
> > >
> > > And with some bisection, I found it's related to this commit,
> > > when I revert this commit, the problem is gone.
> > >
> > > So replied here, not sure if you have any idea about it,
> > > or any suggestions on what we should do next to resolve the problem?
> >
> > FWIW we don't support Android kernels, only kernel.org releases.
>
> Right. If the problem also reproduces on mainline Linux then that
> would be interesting to know. I think db845c is at least somewhat well
> supported by mainline so it should be possible to test it there.

I checked with the ACK android-mainline branch, which is based on the
mainline Linux,
this commit is there, but the problem is not seen.

> If I had to guess, I'd think that probably the CE interrupts are
> firing nonstop for you and not getting handled. Then those constant
> interrupts are (presumably) causing the UFS controller to timeout. If
> this is true, the question is: why? Maybe you could use ftrace to
> confirm this by adding some traces to
> ath10k_snoc_per_engine_handler()? There's a way to get ftrace buffers
> dumped on panic (or, if you use kdb, it has a command for it).

Thanks for the suggestions, I will check internally on how to debug that.

> If this reproduces on mainline and it's not obvious how to fix this, I
> don't object to a revert. As per the description of the original
> patch, the problem being fixed was fairly rare and I didn't have a way
> to reproduce it. The fix seemed safe to me and we've been using it on
> Chromebooks based on sc7180, but if it had to get reverted it wouldn't
> be the end of the world.
>
> -Doug



-- 
Best Regards,
Yongqin Liu
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