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| author | Colin Cross <ccross@android.com> | 2012-08-07 19:05:10 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-08-11 09:15:58 +0100 |
| commit | 237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b (patch) | |
| tree | 17a21e6c00129a703d906166f0e640089e3af6b7 /arch/arm/include/asm/sched_clock.h | |
| parent | f1898f6be9a2e3690fb62d8307849b86a89cc36c (diff) | |
| download | linux-237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b.tar.gz linux-237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b.tar.bz2 linux-237ec6f2e51d2fc2ff37c7c5f1ccc9264d09c85b.zip | |
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 <ccross@android.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/sched_clock.h')
| -rw-r--r-- | arch/arm/include/asm/sched_clock.h | 2 |
1 files changed, 2 insertions, 0 deletions
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 |