On Thu, Nov 29, 2018 at 05:56:31PM -0500, Dietmar May wrote:
I've run into some problems which appear due to (a) recent patch(es)
on the wlcore wifi driver.
4.4.160 - commit 3fdd34643ffc378b5924941fad40352c04610294
4.9.131 - commit afeeecc764436f31d4447575bb9007732333818c
Earlier versions (4.9.130 and 4.4.159 - tested back to 4.4.49) do not
exhibit this problem. It is still present in 4.9.141.
master as of 4.20.0-rc4 does not exhibit this problem.
Basically, during client association when in AP mode (running
hostapd), handshake may or may not complete following a noticeable
delay. If successful, then the driver fails consistently in
warn_slowpath_null during disassociation. If unsuccessful, the wifi
client attempts multiple times, sometimes failing repeatedly. I've had
clients unable to connect for 3-5 minutes during testing, with the
syslog filled with dozens of backtraces. syslog details are below.
I'm working on an embedded device with a TI 3352 ARM processor and a
murata wl1271 module in sdio mode. We're running a fully patched
ubuntu 18.04 ARM build, with a kernel built from kernel.org's
stable/linux repo <https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.9.y&id=afeeecc764436f31d4447575bb9007732333818c>.
Relevant parts of the kernel config are included below.
The commit message states:
/I've only seen this few times with the runtime PM patches enabled
so this one is probably not needed before that. This seems to work
currently based on the current PM implementation timer. Let's apply
this separately though in case others are hitting this issue./
We're not doing anything explicit with power management. The device is
an IoT edge gateway with battery backup, normally running on wall
power. The battery is currently used solely to shut down the system
cleanly to avoid filesystem corruption.
The device tree is configured to keep power in suspend; but the device
should never suspend, so in our case, there is no need to call
wl1271_ps_elp_wakeup() or wl1271_ps_elp_sleep(), as occurs in the
patch.
Given that this patch went in through AUTOSEL, I've queued up a revert
of it (sorry for the trouble!).
I'll link this mail in the revert message. If anyone feels that this
patch should be in any of the LTS trees then either reply to this thread
or start a new one on stable@xxxxxxxxxxxxxxx.
--
Thanks,
Sasha
