linux-image-4.19.0-17-amd64: bug in ath10k driver for QCA6174 wifi card
Hi all, starting from Debian Buster (on older kernels it works, on
newer kernels it fails), I have a problem with the Wi-Fi connection of
my PC:
When I connect a Huawei P Smart smartphone to the same wireless
network my PC is on,
my Wi-Fi card hangs indefinitely, thus causing a disconnection, and I
have to force restart it.
I performed a git bisect on the linux kernel git repo finding the
commit that caused the problem, and it is the commit:
e3def6f7ddf88636febb12e1e3e86387a4ce5452
If I revert the changes introduced by this commit, my bug does not
happen anymore.
I also filed a bug to the ath10k driver mailing list, which contains a
little bit more details:
http://lists.infradead.org/pipermail/ath10k/2021-June/012693.html
Note that in this bug I use a newer kernel, to show that the problem
was not fixed by newer versions of the driver. I am afraid this may be
related to a bug in the firmware,
because after that commit, the size of the htt_rx_desc structure
changes, but the driver tells
the device about the memory layout of htt_rx_desc at runtime,
therefore it could be that in the firmware there is some hardcoded
value that makes things fail.
But really this is only handwaving, I tried sniffing the network with
wireshark but I could not find anything strange, even if there must be
something because this bug is only triggered by a specific model of
smartphone, I tried with two different Huawei P Smart 2019 and both
trigger the bug.
Thanks in advance.
Sincerely,
Francesco Magliocca
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