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 16:29:46 +0300	[thread overview]
Message-ID: <87fu2a4mk5.fsf@kamboji.qca.qualcomm.com> (raw)
In-Reply-To: <bc31b06dc4093b8613fbde6a13f16bd7e8c31e82.camel@gmail.com> ("Timur \=\?utf-8\?Q\?Krist\=C3\=B3f\=22's\?\= message of "Tue, 29 May 2018 15:32:05 +0300")

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

> On Tue, 2018-05-29 at 13:21 +0300, Kalle Valo wrote:
>> > 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.
>
> I don't have much experience with this, but will take a look and let
> you know how that goes.

Ok, let me know how it goes. Some info and pointers here:

https://wireless.wiki.kernel.org/en/users/drivers/ath10k/submittingpatches

>> 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?
>
> Yes, tried it just now. The driver can survive 2 simulated hard
> crashes. After the 3rd hard crash, it reproduces the same issue that I
> described in the bugreport: Wifi stops working. I can turn it off. When
> I turn it on again, the whole system hangs completely.
>
> You would expect that a single driver crash should not affect the whole
> system like this, but it does.

Yeah, it definitely should not crash like that. I wonder what has broken
it.

> Is there a chance this is already fixed upstream? In general, which of
> your branches should I try to use with this device? ath-next or
> ath-qca?

I doubt neither of the bugs (the firmware crash and the kernel hang) are
fixed, at least I don't recall seeing any fixes. But if you have time to
test, use the master branch of my ath.git tree for any testing.

https://wireless.wiki.kernel.org/en/users/drivers/ath10k/sources

-- 
Kalle Valo

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