]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
[CPUFREQ] pcc driver should check for pcch method before calling _OSC
authorMatthew Garrett <mjg@redhat.com>
Tue, 20 Jul 2010 17:52:00 +0000 (13:52 -0400)
committerDave Jones <davej@redhat.com>
Mon, 26 Jul 2010 19:25:34 +0000 (15:25 -0400)
commit47f8bcf362410b631a4d99ff5c79ec6b9dd3ace6
tree2c6486e767ec0007a01db589b8eec05d90d148a0
parent6f90388ac98e8cb2c63e307ffb13871a6b87f29b
[CPUFREQ] pcc driver should check for pcch method before calling _OSC

The pcc specification documents an _OSC method that's incompatible with the
one defined as part of the ACPI spec. This shouldn't be a problem as both
are supposed to be guarded with a UUID. Unfortunately approximately nobody
(including HP, who wrote this spec) properly check the UUID on entry to the
_OSC call. Right now this could result in surprising behaviour if the pcc
driver performs an _OSC call on a machine that doesn't implement the pcc
specification. Check whether the PCCH method exists first in order to reduce
this probability.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Signed-off-by: Dave Jones <davej@redhat.com>
arch/x86/kernel/cpu/cpufreq/pcc-cpufreq.c