Sunday, May 17, 2009

Another Fedora 10 Atheros issue

Symptom Brief Description: Ath5k card on Fedora 10 does not come back from suspend.

I could write a book (a relatively short book, but a book nonetheless), on the sheer number and variety of frustrations I've had with the Atheros 5K wireless card on Fedora 10. After initially getting it working, I've lost the card after about 30% of the OS updates I've applied (often to new and interesting issues). There are endless (very good) articles available on the myriad issues with installing the card, or with getting it to connect to a WPA AP. Most of these are more articulate than I would be on these well-documented issues, and can be easily located by Googling the error message, or hitting the Fedora Forum.

I would, however, like to spare others my most recent unnecessary frustration with this card on FC10.

After the last round of updates that I mustered the courage to apply, the wireless card stopped coming back from suspend. The primary symptom I saw was being repeatedly asked for authentication, which, in turn, repeatedly failed. I began to doubt I knew my the password for my AP.

At the time, I couldn't find anything on the issue. In the last couple of months there appear to have been more posts, and Redhat have posted a bug on it. Their recommendation appears to be upgrading to Fedora 11 (which I have not done, nor have I seen verification that this solves the problem). No workaround is posted.

Error Messages:
A tail of the message log showed the following errors.

May 17 16:39:49 localhost kernel: ath5k phy0: gain calibration timeout (2422MHz)
May 17 16:39:49 localhost kernel: ath5k phy0: ath5k_chan_set: unable to reset channel (2422 Mhz)
May 17 16:39:50 localhost NetworkManager: wlan0: link timed out.
May 17 16:39:50 localhost kernel: ath5k phy0: gain calibration timeout (2427MHz)
May 17 16:39:50 localhost kernel: ath5k phy0: ath5k_chan_set: unable to reset channel (2427 Mhz)

As the error clearly says it is "unable to reset channel." This sounds like something a reboot should fix. A reboot, however, results only in:

ath5k phy0: unable to reset hardware: -11

Things you probably shouldn't bother doing:

In trying to get back up and running, I spent unnecessary time beating my head against a wall -- due primarily to my own impatience. I went on a wild goose chase of blind troubleshooting. All of the below were useless in fixing the issue:

  • Warm reboot
  • Hard shutdown allowing only a brief 'off' time.
  • Reinstalling the driver,
  • Attempting to backrev the driver,
  • Attempting to go back to the old madwifi driver,
  • Assuming it was a WPA issue and generally digging myself into a deeper hole.
Do not do these things! I lost three 'Alice in Wonderland-esque' hours of inexplicable frustration 'down the rabbit-hole' (so to speak).

How to 'fix'/workaround it:
Eventually, I shut down out of frustration and came back later. Naturally, this was what solved the issue. It appears that when you shut down, you really have to mean it, and give it a few minute to be sure it's learned its lesson.

I've run into this a couple of times since then, and a reboot, even completely shutting down for a minute or so, does not fix it. Shutting down for several minutes is the only thing that's got me back up and running. I've also found that I can restart in only a couple of minutes if I go the extra mile of removing power and battery. This may be overkill. It may also be the case that it's not necessary to physically leave the room in order to shame my laptop into cooperation. You may think it 'ridiculous' to go so far as to put your laptop in the dog's crate to give it a time out I, however, feel these are all viable (and somewhat satisfying) options.

The actual problem/anticipated long-term fix:
Of course, this is not a satisfactory solution (the dog needs his crate back). If FC11 really does solve the issue, I may eventually become optimist enough to move forward without expecting the same Sysiphusian drudgery (with regard only to the Atheros card -- I've been very happy with FC8, 9, and 10 otherwise and appreciate the work done to maintain a free O/S) on the new release. Until then, I'll be shutting down, crossing my fingers, and hoping for an interim fix.

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