From 237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Tue, 7 Aug 2012 19:05:10 +0100 Subject: ARM: 7486/1: sched_clock: update epoch_cyc on resume Many clocks that are used to provide sched_clock will reset during suspend. If read_sched_clock returns 0 after suspend, sched_clock will appear to jump forward. This patch resets cd.epoch_cyc to the current value of read_sched_clock during resume, which causes sched_clock() just after suspend to return the same value as sched_clock() just before suspend. In addition, during the window where epoch_ns has been updated before suspend, but epoch_cyc has not been updated after suspend, it is unknown whether the clock has reset or not, and sched_clock() could return a bogus value. Add a suspended flag, and return the pre-suspend epoch_ns value during this period. The new behavior is triggered by calling setup_sched_clock_needs_suspend instead of setup_sched_clock. Signed-off-by: Colin Cross Reviewed-by: Linus Walleij Signed-off-by: Russell King --- arch/arm/include/asm/sched_clock.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm/include/asm/sched_clock.h') diff --git a/arch/arm/include/asm/sched_clock.h b/arch/arm/include/asm/sched_clock.h index e3f757263438..05b8e82ec9f5 100644 --- a/arch/arm/include/asm/sched_clock.h +++ b/arch/arm/include/asm/sched_clock.h @@ -10,5 +10,7 @@ extern void sched_clock_postinit(void); extern void setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate); +extern void setup_sched_clock_needs_suspend(u32 (*read)(void), int bits, + unsigned long rate); #endif -- cgit v1.2.3