Using iw and powertop and laptop-mode-tools to turn on powersave mode for wlan chip in my laptop (which is an AR9462) fails. In powertop nothing happens, but if I run the --calibrate script the program segfaults when testing the wlan chip. As for iw it returns:
command failed: Operation not supported (-95)
And laptop-mode returns:
Error for wireless request "Set Power Management" (8B2C) :
SET failed on device wlan0 ; Operation not supported.
All these things started to fail after I updated my kernel to 3.13, the most recent kernel in Debian testing (I use #! and pull in a few packages from testing). After doing some snooping I came across this in the kernel changelog:
Author: Sujith Manoharan <email@example.com>
Date: Tue Feb 4 08:37:53 2014 +0530
ath9k: Do not support PowerSave by default
commit 8298383c2cd5a6d0639f1bb1781fba181bd20154 upstream.
Even though we make sure PowerSave is not enabled by default
by disabling the flag, WIPHY_FLAG_PS_ON_BY_DEFAULT on init,
PS could be enabled by userspace based on various factors
like battery usage etc. Since PS in ath9k is just broken
and has been untested for years, remove support for it, but
allow a user to explicitly enable it using a module parameter.
Signed-off-by: Sujith Manoharan <firstname.lastname@example.org>
Signed-off-by: John W. Linville <email@example.com>
Signed-off-by: Greg Kroah-Hartman <firstname.lastname@example.org>
Could this potentially be the problem? And if so how do I enable the powersave module parameter, as the powersave feature still worked for me in kernel 3.12. It does make a difference, as I get about 1-2 hours of more battery life with this option enabled.
Here is my lspci dump for the device.
03:00.0 Network controller: Atheros Communications Inc. AAR9462 Wireless Network Adapter (rev 01)
Subsystem: Foxconn International, Inc. Device e052
Kernel driver in use: ath9k