Subject: speedstep does the wrong thing after 'resume'
To: None <firstname.lastname@example.org>
From: Steven M. Bellovin <email@example.com>
Date: 12/26/2004 20:25:25
On a Thinkpad T42 with ENHANCED_SPEEDSTEP enabled, the CPU frequency
seems to be reset to maximum after a resume. I ran a loop checking the
current frequency every 5 seconds. I went to battery; the CPU speed
dropped appropriately, via my /etc/apm/batter script. I then suspended
the machine; when I resumed, the CPU speed was set to maximum. My fix
is to include this text in /etc/apm/resume:
case `apm -d -a` in
0|2) sh /etc/apm/battery;;
1) sh /etc/apm/line;;
I think (but haven't verified) that the system misses transitions to/
from line power on a resume. This script will catch that, too.
--Prof. Steven M. Bellovin, http://www.cs.columbia.edu/~smb