Re: Frequent ath10k crashes with QCA6174 on kernels 4.16 and 4.17

From: Kalle Valo <kvalo@codeaurora.org>
To: "Timur Kristóf" <timur.kristof@gmail.com>
Cc: ath10k@lists.infradead.org, ryanhsu@codeaurora.org
Subject: Re: Frequent ath10k crashes with QCA6174 on kernels 4.16 and 4.17
Date: Tue, 29 May 2018 13:21:44 +0300	[thread overview]
Message-ID: <87po1e69tz.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <c92e04d5b80af2a640ab97efce32d987ffb27ffe.camel@gmail.com> ("Timur \=\?utf-8\?Q\?Krist\=C3\=B3f\=22's\?\= message of "Tue, 29 May 2018 11:52:15 +0300")

+ ryan

Timur Kristóf <timur.kristof@gmail.com> writes:

> I'm experiencing a lot of ath10k driver crashes on both 4.16 (as
> shipped in Fedora) and 4.17 (tried rc5 and rc6) using a Dell XPS 13
> 9370 with a QCA6174.
>
> With 4.16 the driver crash always results in the whole system hanging.
> With 4.17 it does not always hang the system completely, but it still
> happends. I also tried to upgrade the firmware which also reduces the
> frequency of the crashes but does not eliminate them completely.
>
> The common pattern I see in dmesg is this:
> [30372.900832] wlp2s0: AP 64:7c:34:3f:c3:b0 changed bandwidth, new
> config is 2437 MHz, width 2 (2447/0 MHz)
>
> Searching a bit in kernel sources, this message is printed by this line:
> https://github.com/torvalds/linux/blob/master/net/mac80211/mlme.c#L364
> And width 2 seems to correspond to NL80211_CHAN_WIDTH_40 here:
> https://github.com/torvalds/linux/blob/master/include/uapi/linux/nl80211.h#L3880
>
> So it seems that either the driver or the firmware can't cope with it
> when the AP changes the bandwidth.
> Here is the Fedora bug report:
> https://bugzilla.redhat.com/show_bug.cgi?id=1577106
>
> Is there anything that can be done to improve the stability of ath10k on this system?
> I see there is a lot going on in the upstream repo, but not sure which
> branch to try: ath-next or qca?

I think this patch should fix the firmware crash:

ath10k: Update the phymode along with bandwidth change request

https://patchwork.kernel.org/patch/10183453/

Unfortunately it didn't apply to my tree so I had to drop it. Few days
ago I was talking with Ryan and he said he is planning to send v2, but
I'm sure he don't mind if someone else can send the v2 either. The
faster we can apply the patch, and get it to stable releases, the better
as we seems to be a very common issue.

But there also seems to be another bug related to firmware restart, it
shouldn't crash the kernel! Does the kernel crash also when crashing the
kernel using simulate_fw_crash debugfs file?

-- 
Kalle Valo

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