So I upgraded the firmware on my Intel NUC (NUC6i3SYK), and that made
the wireless no longer work with a 4.5 kernel. I could get the
occasional packets through, but not many, and ti would hang for ten
seconds at a time, and then output errors like
iwlwifi 0000:01:00.0: Queue 2 stuck for 10000 ms.
iwlwifi 0000:01:00.0: Current SW read_ptr 60 write_ptr 93
..
which was odd, because that kernel had worked fine before.
I booted between two different kernels, going back to an older 4.5-rc3
one that had been running a lot longer on that machine, because
initially I thought that this was some recent kernel failure (I didn't
initially connect it with the firmware upgrade, because this is my
kids machine and I hadn't tested networking after the firmware
update). But that older known-good kernel failed the same way.
Going all the way back to the 4.4 kernel that Fedora uses made
wireless work, and then rebooting back into a 4.5 kernel also worked.
Now, it's *possible* that it was just something odd and transient and
it just happened to clear up as I rebooted into the Fedora kernel, but
it feels more likely that there's some incomplete initialization in
recent 4.5 kernels, which isn't normally noticeable, but the full
system reset done as part of the firmware upgrade might have shown it.
I'm attaching all the iwlwifi debug output that goes along with the
stuck queue, in the hopes that it makes sense to somebody. This is
from the 4.5-rc3 boot into an older kernel, but final 4.5 showed the
same behavior.
Googling iwlwifi stuck queues shows a lot of reports over the years,
but it might be a common symptom of "something is screwed up".
I'm not sure I can reproduce it any more now that it works again (and
I'm not really willing to force a firmware downgrade), but if there is
something particular to test, I can do that.
Ideas?
Linus
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celeste-wifi-problem
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