>> When doing block i/o on the dvd drive (dd if=/dev/hdc of=/dev/null), >> the mouse moves randomly and the pmu reports spurious dead battery >> conditions. During the dd, use of the trackpad causes random pointer >> motion. The battery is intermittently reported at 2% or 3%, even when >> fully charged and plugged in. > >I had a similar problem here. However, I was clued on IRC (credits go to >Michael Daenzer) and a fix to the problem seems to be to just enable DMA >and unmask IRQ via hdparm. This also works if one uses ide-scsi, just try >hdparm -d1 -u1 /dev/hdx. (Replace x by c and do not read the manpage of >hdparm, it is just too scary... :) ) So e.g. one can place the line >post-install ide-scsi hdparm -u1 -d1 /dev/hdx in /etc/modutils/foobar and >enjoy.
The question is why DMA would have been disabled in the first place ? The kernel is enabling DMA by default on all devices that support it connected to the Apple IDE interface. Ben.
