tree 9a507164ea05a12227d8301341085dc07f5e7936
parent ca18ed4416bb83d91e6759ae6d9cfd84e2b11442
author Martin Willi <martin@strongswan.org> 1534923592 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1542136496 -0800

ath10k: schedule hardware restart if WMI command times out

[ Upstream commit a9911937e7d332761e8c4fcbc7ba0426bdc3956f ]

When running in AP mode, ath10k sometimes suffers from TX credit
starvation. The issue is hard to reproduce and shows up once in a
few days, but has been repeatedly seen with QCA9882 and a large
range of firmwares, including 10.2.4.70.67.

Once the module is in this state, TX credits are never replenished,
which results in "SWBA overrun" errors, as no beacons can be sent.
Even worse, WMI commands run in a timeout while holding the conf
mutex for three seconds each, making any further operations slow
and the whole system unresponsive.

The firmware/driver never recovers from that state automatically,
and triggering TX flush or warm restarts won't work over WMI. So
issue a hardware restart if a WMI command times out due to missing
TX credits. This implies a connectivity outage of about 1.4s in AP
mode, but brings back the interface and the whole system to a usable
state. WMI command timeouts have not been seen in absent of this
specific issue, so taking such drastic actions seems legitimate.

Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>