Regular firmware crashes with QCA6174

[Michal Kazior]

On 9 January 2017 at 13:36, Shaun Crampton <shaun at cantab.net> wrote:
> On Mon, 9 Jan 2017, 08:49 Michal Kazior, <michal.kazior at tieto.com> wrote:
>> On 7 January 2017 at 22:41, Shaun Crampton <shaun at cantab.net> wrote:
>> > Hi,
>> >
>> > I'm getting regular QCA6174 firmware crashes on Ubuntu 16.10 with the
>> > QCA6174 (new Dell XPS 13, which shipped with Ubuntu 16.04).  Crash
>> > seems to be at random, roughly every 30 minutes.  After the crash,
>> > wifi stops working until I turn it off and on again.
>> >
>> > Any help or workaround appreciated.  I've copied the dmesg log in
>> > below.  I have the latest firmware from linux-firmware in
>> > /lib/firmware.
>> >
>> > Please CC in me any responses.
>> >
>> > Thanks,
>> >
>> > -Shaun
>> >
>> > [ 3683.563419] wlp58s0: AP 00:07:26:aa:e0:45 changed bandwidth, new
>> > config is 2472 MHz, width 2 (2462/0 MHz)
>>
>> Your AP seems to be toggling HT20 and HT40.
>>
>> Can you force your AP to run at HT20 at all times, please? If the
>> problem ceases it'll strongly point to firmware's rate control
>> becoming confused (e.g. due to driver not properly telling it how
>> peer's capabilities have changes).
>
> I don't think my AP has that setting, is there any way to disable it at the
> client side?

APs can expose this differently, e.g. mode (a/b/g/n), bandwidth (20,
40, auto), rate (54, 150, 300, 866). In any case, you want to avoid
"n/ac", >54mbps, !=20mhz.

You could force wpa_supplicant to run with disabe_ht=1 in the network
block to force legacy 11a/b/g mode which should ignore bandwidth
changes. I don't know how to force network manager (or similar) to do
that though.


Michał