ath11k: QCA6390 on Dell XPS 13 and kernel crashes

[wi nk]

On Mon, Nov 30, 2020 at 6:02 PM wi nk <wink at technolu.st> wrote:
>
> On Mon, Nov 30, 2020 at 5:55 PM Kalle Valo <kvalo at codeaurora.org> wrote:
> >
> > Hi Wi and Thomas,
> >
> > I'll start a new thread about problems on XPS 13. The information is
> > scattered to different threads and hard to find everything, it's much
> > easier to have everything in one place. So let's continue the discussion
> > about the kernel crashes on this thread.
> >
> > Here's what I have understood so far:
> >
> > * On Dell XPS 15 there are no issues with QCA6390 and it seems to work
> >   with 32 MSI vectors.
> >
> > * On Dell XPS 13 there's a BIOS bug and kernel prints:
> >
> > [    0.050130] DMAR: [Firmware Bug]: Your BIOS is broken; DMAR reported at address 0!
> >                BIOS vendor: Dell Inc.; Ver: 1.1.1; Product Version:
> >
> > * Because of this BIOS bug QCA6390 only gets one MSI vector on Dell XPS
> >   13. We added a hack to ath11k make it work with only vector and after
> >   that it's possible to boot the firmware, connect to the AP and use the
> >   device for a while.
> >
> > * But the problem now is that the kernel is crashing almost immediately
> >   and almost every time(?). And these crashes only happen on Dell XPS
> >   13, all other systems (including Dell XPS 15) seem to work without
> >   issues.
> >
> > Is my understanding correct? Did I miss anything?
> >
> > About the symptoms Wi reports:
> >
> > ----------------------------------------------------------------------
> > So up until this point, everything is working without issues.
> > Everything seems to spiral out of control a couple of seconds later
> > when my system attempts to actually bring up the adapter.  In most of
> > the crash states I will see this:
> >
> > [   31.286725] wlp85s0: send auth to ec:08:6b:27:01:ea (try 1/3)
> > [   31.390187] wlp85s0: send auth to ec:08:6b:27:01:ea (try 2/3)
> > [   31.391928] wlp85s0: authenticated
> > [   31.394196] wlp85s0: associate with ec:08:6b:27:01:ea (try 1/3)
> > [   31.396513] wlp85s0: RX AssocResp from ec:08:6b:27:01:ea
> > (capab=0x411 status=0 aid=6)
> > [   31.407730] wlp85s0: associated
> > [   31.434354] IPv6: ADDRCONF(NETDEV_CHANGE): wlp85s0: link becomes ready
> >
> > And then either somewhere in that pile of messages, or a second or two
> > after this my machine will start to stutter as I mentioned before, and
> > then it either hangs, or I see this message (I'm truncating the
> > timestamp):
> >
> > [   35.xxxx ] sched: RT throttling activated
> >
> > After that moment, the machine is unresponsive.  Sorry I can't seem to
> > extract this data other than screenshots from my phone at the moment,
> > you can see the dmesg output from 6 different hangs here:
> >
> > https://github.com/w1nk/ath11k-debug
> > ----------------------------------------------------------------------
> >
> > And Thomas Krause reports:
> >
> > --------------------------------------------------------------------------------
> > I can confirm this behavior on my configuration. I managed to login
> > once and select the Wifi and connect to it. It seemed curiously enough
> > be stable long enough to enter the Wifi passphrase. After the
> > connection was established, the system hang and on each attempt to
> > reboot into the graphical system it would freeze at some point
> > (sometimes even before showing the login screen).
> > ----------------------------------------------------------------------
> >
> > --
> > https://patchwork.kernel.org/project/linux-wireless/list/
> >
> > https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
>
> Hi Kalle,
>
>   Again, thanks much for your work.  I think you've summarized
> everything up until this point.  On my XPS 13 9310 The behavior of the
> RT throttling still exists for me occasionally on loading the
> driver/associating with an AP.  The throttling consistently occurs
> after a few sets of the MHI debug printing showing the EE entering an
> invalid state ( AMSS -> INVALID_EE ).  I'm now building the latest tag
> to see if there are any differences.
>
> Thanks!

Just to follow up, the first boot resulted in the RT throttling
message as the adapter was coming up/associating, shortly after the
firmware crashed and the kernel didn't fully freeze, but I needed to
reboot to bring the adapter back.