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| author | Dave Martin <dave.martin@linaro.org> | 2011-05-24 13:11:48 +0200 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-05-26 11:31:06 +0200 |
| commit | 2846d84ffa4408c9810fabad74cb7aec410352fc (patch) | |
| tree | 25e0a37c87f283e24808ecceb84bb846f9e49e07 | |
| parent | ARM: 6938/1: fiq: Refactor {get,set}_fiq_regs() for Thumb-2 (diff) | |
| download | linux-2846d84ffa4408c9810fabad74cb7aec410352fc.tar.xz linux-2846d84ffa4408c9810fabad74cb7aec410352fc.zip | |
ARM: 6940/1: fiq: Briefly document driver responsibilities for suspend/resume
Drivers which make use of the FIQ interrupt may require the state
of the FIQ mode registers to be preserved across suspend/resume.
Because the FIQ mode registers are not saved and restored
automatically by the kernel, driver authors will need to do the
appropriate save/restore in their own driver suspend/resume
handlers.
Implementing global automatic save/restore of the FIQ state does
not appear appropriate, since this by itself is not sufficient for
FIQ-based drivers to function correctly across suspend/resume in
any case.
This patch adds a brief explanatory note to fiq.h documenting the
requirement placed on driver authors.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
| -rw-r--r-- | arch/arm/include/asm/fiq.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm/include/asm/fiq.h b/arch/arm/include/asm/fiq.h index 45bb3eeeab7c..d493d0b742a1 100644 --- a/arch/arm/include/asm/fiq.h +++ b/arch/arm/include/asm/fiq.h @@ -4,6 +4,13 @@ * Support for FIQ on ARM architectures. * Written by Philip Blundell <philb@gnu.org>, 1998 * Re-written by Russell King + * + * NOTE: The FIQ mode registers are not magically preserved across + * suspend/resume. + * + * Drivers which require these registers to be preserved across power + * management operations must implement appropriate suspend/resume handlers to + * save and restore them. */ #ifndef __ASM_FIQ_H |