[regression] mhi: ath11k resume fails on some devices

[Manivannan Sadhasivam]

On Thu, Oct 21, 2021 at 03:33:05PM +0530, Manivannan Sadhasivam wrote:
> 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.
> 

I'm able to reproduce the issue on my NUC. I'm still investigating on how to
properly fix this issue. Expect a patch soon.

Thanks,
Mani 

> 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.
> > 
> > -- 
> > https://patchwork.kernel.org/project/linux-wireless/list/
> > 
> > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches