Description of problem: For the two or three latest 2.6.38 RC kernel builds , driver ath5k exhibits calibration timeouts causing the loss of wireless connectivity. Output of log file /var/log/dmesg shows many trailing lines "ath5k phy0: gain calibration timeout .." , and NM tries repeatedly to reconnect, alas without success. Version-Release number of selected component (if applicable): kernel-2.6.38-0.rc2.git3.2.fc15 How reproducible: Always. Steps to Reproduce: 1. Boot system. 2. Connect to AP. Actual results: NM brings up a wireless connection which only lasts a few minutes. Expected results: NM brings up a stable wireless connection. Additional info: - Wireless interface is a D-Link DWL-G520 Rev. B4 (Atheros AR2413). - A system reboot is needed to restore wireless connectivity. - Upstream bug at https://bugzilla.kernel.org/show_bug.cgi?id=27382 . - Driver ath5k used to work reliably for kernel-2.6.37-2.fc15.
Reverting successively to earlier kernel builds, it appears that the issue is present from kernel 2.6.38-0.rc2.git1.3.fc15 on, thus 2.6.38-0.rc2.git1.3.fc15 : FAILURE 2.6.38-0.rc2.git1.1.fc15 : SUCCESS According to the changelog, only a vendor patch has been applied between these two builds: * Mon Jan 24 2011 Kyle McMartin <kmcmartin redhat com> 2.6.38-0.rc2.git1.3 - Disable usb/pci/acpi autosuspend goo until it can be checked.
After half a day of using kernel 2.6.38-0.rc2.git1.1.fc15, a gain calibration timeout eventually occurred, too, whereas for more recent kernels it happened within a couple of minutes. This observation supports the conjecture of dealing with a genuine 2.6.38 issue.
Created attachment 476753 [details] Patch for fast channel switch Patch fixing the fast channel fix issue provided by Nick Kossifis at https://bugzilla.kernel.org/show_bug.cgi?id=27382#c32 . Please include it into the next F15 kernel build in order to work around the current issue until it gets fixed upstream. Tge latest kernel-2.6.38-0.rc3.git0.1.fc15 is still affected by this issue making it unusable for people relying on wireless network. Thanks!
I am finding this problem happening again. I updated my system with yum update on 2012-04-25. lots of "ath5k phy0: gain calibration timeout" in dmesg GUI manager allows dis/enabling wireless but shows no networks. I have not used the wireless for some time, so can't say whether it was broken by recent updates, or has been broken a long time. F16 x86_64 I've tried rebooting with kernels from 3.2.10-3 to 3.3.2-6 . reboots do not help. Can someone reopen this report?
In my case, emoving the battery restores network connectivity, as reported in similar bugs from 2009, 2010, 2011: https://bugzilla.redhat.com/show_bug.cgi?id=478395 https://bugzilla.redhat.com/show_bug.cgi?id=638943 https://bugzilla.redhat.com/show_bug.cgi?id=672778