tree 37ddc23737bced60a8defc52f643f362e2744908
parent ec22559e0b7a05283a3413bda5d177e42c950e23
author Stuart_Hayes@Dell.com <Stuart_Hayes@Dell.com> 1178207929 -0700
committer Greg Kroah-Hartman <gregkh@suse.de> 1184282985 -0700

USB: EHCI cpufreq fix

EHCI controllers that don't cache enough microframes can get MMF errors
when CPU frequency changes occur between the start and completion of
split interrupt transactions, due to delays in reading main memory
(caused by CPU cache snoop delays).

This patch adds a cpufreq notifier to the EHCI driver that will
inactivate split interrupt transactions during frequency transitions.
It was tested on Intel ICH7 and Serverworks/Broadcom HT1000 EHCI
controllers.

Signed-off-by: Stuart Hayes <stuart_hayes@dell.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>