> It now seems to me that this is not a iwl4965 bug. > The 'fix' no longer seems to work. > > However on the same hardware Ubuntu (2.6.24) and Rawhide (2.6.26) do not > exhibit the problem (regardless of the power_level setting) but Fedora 9 > (2.6.25) does have the problem.
This appears to me to be yet another example of a problem that has been reported in the past in various places including this mailing list. (See http://www.bughost.org/pipermail/power/2007-May/000337.html http://www.bughost.org/pipermail/power/2007-October/000998.html http://www.bughost.org/pipermail/power/2008-March/001327.html and others.) It doesn't seem likely that the strange behaviour is related to beacon responses, because these responses should generate an interrupt that is picked up by powertop. However, it is entirely possible that the iwl4965 (and iwl3965) are the sources of the strange behaviour, through some other mechanism, perhaps abberant DMA activity (possibly even aberrant DMA requests) or some other mechanism that causes a wakeup that is not counted by powertop. Of course, it is also entirely possible that some other part of the computer is responsible. I've seen lots of attempts at explaining the problem, but nearly all of them either can't explain how there are so many wakeups (sometimes over 40K/s) or why powertop doesn't pick up any reason for the wakeups. This is why I'm leaning to the DMA explanation, even though I know very little about Linux internals. It sure would be nice to have some knowledgeable person take a look at the issue and start on a resolution. I'm willing to try out various things on my machine, but I haven't noticed the behaviour for a while now. My experience is that the problem comes and goes, so I wouldn't exonerate Ubuntu and Rawhide just yet. Peter F. Patel-Schneider _______________________________________________ Power mailing list [email protected] http://www.bughost.org/mailman/listinfo/power
