From: Martin Schwidefsky Date: Fri, 14 Aug 2009 13:47:20 +0000 (+0200) Subject: timekeeping: Move reset of cycle_last for tsc clocksource to tsc X-Git-Tag: v2.6.32-rc1~168^2~26 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1be396794897f80bfc8774719ba60309a9e3d374;p=pandora-kernel.git timekeeping: Move reset of cycle_last for tsc clocksource to tsc change_clocksource resets the cycle_last value to zero then sets it to a value read from the clocksource. The reset to zero is required only for the TSC clocksource to make the read_tsc function work after a resume. The reason is that the TSC read function uses cycle_last to detect backwards going TSCs. In the resume case cycle_last contains the TSC value from the last update before the suspend. On resume the TSC starts counting from 0 again and would trip over the cycle_last comparison. This is subtle and surprising. Move the reset to a resume function in the tsc code. Signed-off-by: Martin Schwidefsky Acked-by: Thomas Gleixner Acked-by: John Stultz Cc: Daniel Walker LKML-Reference: <20090814134808.142191175@de.ibm.com> Signed-off-by: Thomas Gleixner --- Reading git-diff-tree failed