[linux-audio-user] Latency issues with laptops

[Lee Revell]

One of the JACK developers reported this problem on LKML and the reply
was very interesting, this could explain a lot of the weird latency
issues that laptop users are seeing.

http://lkml.org/lkml/2004/10/11/182

The basic issue seems to be if your laptop has a broken BIOS which
implements ACPI using SMM you are out of luck.  Here is some more
information on the problem (near the end of the page):

http://www.infoworld.com/cgi-bin/displayNew.pl?/glass/bg112596.htm

If ACPI causes you massive xrun/latency problems then you might have
such a broken BIOS.  If you are having weird latency problems with a
laptop, even with ACPI disabled, try to see if it corresponds to the fan
turning on or changing speed.  If so then you might be screwed :-(

There does not seem to be a lot of hope if you do have one of these
broken machines.  But we can at least identify the problematic laptops,
complain to the manufacturers, and warn people not to buy them.

Lee