[regression] mhi: ath11k resume fails on some devices

[Manivannan Sadhasivam]

On Tue, Oct 19, 2021 at 03:12:01PM +0300, Kalle Valo wrote:
> Kalle Valo <kvalo at codeaurora.org> writes:
> 
> > (adding the new mhi list, yay)
> >
> > Hi Loic,
> >
> > Loic Poulain <loic.poulain at linaro.org> writes:
> >
> >>> Loic Poulain <loic.poulain at linaro.org> writes:
> >>>
> >>> > On Thu, 16 Sept 2021 at 10:00, Kalle Valo <kvalo at codeaurora.org> wrote:
> >>>
> >>> >> At the moment I'm running my tests with commit 020d3b26c07a reverted and
> >>> >> everything works without problems. Is there a simple way to fix this? Or
> >>> >> maybe we should just revert the commit? Commit log and kernel logs from
> >>> >> a failing case below.
> >>> >
> >>> > Do you have log of success case?
> >>>
> >>> A log from a successful case in the end of email, using v5.15-rc1 plus
> >>> revert of commit 020d3b26c07abe27.
> >>>
> >>> > To me, the device loses power, that is why MHI resuming is failing.
> >>> > Normally the device should be properly recovered/reinitialized. Before
> >>> > that patch the power loss was simply not detected (or handled at
> >>> > higher stack level).
> >>>
> >>> Currently in ath11k we always keep the firmware running when in suspend,
> >>> this is a workaround due to problems between mac80211 and MHI stack.
> >>> IIRC the problem was something related MHI creating struct device during
> >>> resume or something like that.
> >>
> >> Could you give a try with the attached patch? It should solve your
> >> issue without breaking modem support.
> >
> > Sorry for taking so long, but I now tested your patch on top of
> > v5.15-rc3 and, as expected, everything works as before with QCA6390 on
> > NUC x86 testbox.
> >
> > Tested-by: Kalle Valo <kvalo at codeaurora.org>
> 
> I doubt we will find enough time to fully debug this mhi issue anytime
> soon. Can we commit Loic's patch so that this regression is resolved?
> 

Sorry no :( Eventhough Loic's patch is working, I want to understand the
issue properly so that we could add a proper fix or patch the firmware
if possible.

Let's try to get the debug logs as I requested.

Thanks,
Mani

> At the moment I'm doing all my regression testing with commit
> 020d3b26c07abe27 reverted. That's a risk, I would prefer to do my
> testing without any hacks.
> 
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