ath wireless power management failure

[Ricardo Wurmus]

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net
Hi Guix,

since a couple of days I’m experiencing problems with my wireless card
after waking up from suspend.  I suspend the laptop very often, so this
is really important to me.

Upon waking up from suspend the wireless card cannot be initialised any
more.  This results in a constant stream of error messages, which can be
seen in dmesg.  The messages disappear when unloading all ath-related
kernel modules.  Reloading the modules does not return the network card
to a workable state, so I have to reboot if I want to connect to a
wireless network (and I usually want to do that).

The error messages that appear in the log look like this:

--8<---------------cut here---------------start------------->8---
[ 1210.998408] ath: phy0: Unable to reset channel, reset status -22
[ 1211.078027] ath: phy0: DMA failed to stop in 10 ms AR_CR=0xffffffff 
AR_DIAG_SW=0xffffffff DMADBG_7=0xffffffff
[ 1211.078038] ath: phy0: Could not stop RX, we could be confusing the DMA 
engine when we start RX up
--8<---------------cut here---------------end--------------->8---

(Repeat ad infinitum.)

According to ancient bug reports these messages relate to power
management problems and have been reported as fixed a long time ago.  I
confirmed with “iw” and “iwconfig” that power management for my WiFi
card is in fact disabled (I didn’t do this myself).

I see these errors with linux-libre-4.1 and linux-libre.  I’m using
a somewhat dated Libreboot (planning to upgrade *after* FOSDEM to be
sure that my machine is usable for the presentation).

Has anyone else experienced the same behaviour?  Any ideas how to fix
this?  Does this just mean that my WiFi card is dying?

--
Ricardo