[PATCH] OMAP3: disable idle during the entire suspend/resume sequence

[PATCH] OMAP3: disable idle during the entire suspend/resume sequence

[jean.pihet]

From: Jean Pihet <j-pihet@ti.com>

Idle path should be disabled during the entire suspend/resume sequence.
Currently it is disabled in ->prepare() and re-enabled in ->finish(),
but the suspend sequence starts with ->begin() and ends with ->end(),
leaving windows where the suspend/resume sequence is still underway and
idle code could execute.

The fix is to move the idle disable (disable_hlt) and enable (enable_hlt)
into ->begin() and ->end() respectively to ensure that the idle path
is disabled for the entire suspend/resume sequence.
Remvoving omap3_pm_prepare and omap3_pm_finish since there are now empty.

Tested with RET and OFF on Beagle and OMAP3EVM.

Signed-off-by: Jean Pihet <j-pihet@ti.com>

Comment rework suggested by Kevin.

Cc: Kevin Hilman <khilman@deeprootsystems.com>
---
 arch/arm/mach-omap2/pm34xx.c |   15 ++-------------
 1 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 75c0cd1..2e0621e 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -506,12 +506,6 @@ out:
 #ifdef CONFIG_SUSPEND
 static suspend_state_t suspend_state;
 
-static int omap3_pm_prepare(void)
-{
-	disable_hlt();
-	return 0;
-}
-
 static int omap3_pm_suspend(void)
 {
 	struct power_state *pwrst;
@@ -574,14 +568,10 @@ static int omap3_pm_enter(suspend_state_t unused)
 	return ret;
 }
 
-static void omap3_pm_finish(void)
-{
-	enable_hlt();
-}
-
 /* Hooks to enable / disable UART interrupts during suspend */
 static int omap3_pm_begin(suspend_state_t state)
 {
+	disable_hlt();
 	suspend_state = state;
 	omap_uart_enable_irqs(0);
 	return 0;
@@ -591,15 +581,14 @@ static void omap3_pm_end(void)
 {
 	suspend_state = PM_SUSPEND_ON;
 	omap_uart_enable_irqs(1);
+	enable_hlt();
 	return;
 }
 
 static struct platform_suspend_ops omap_pm_ops = {
 	.begin		= omap3_pm_begin,
 	.end		= omap3_pm_end,
-	.prepare	= omap3_pm_prepare,
 	.enter		= omap3_pm_enter,
-	.finish		= omap3_pm_finish,
 	.valid		= suspend_valid_only_mem,
 };
 #endif /* CONFIG_SUSPEND */
-- 
1.7.2.3

Re: [PATCH] OMAP3: disable idle during the entire suspend/resume sequence

[Kevin Hilman]

jean.pihet@newoldbits.com writes:

> From: Jean Pihet <j-pihet@ti.com>
>
> Idle path should be disabled during the entire suspend/resume sequence.
> Currently it is disabled in ->prepare() and re-enabled in ->finish(),
> but the suspend sequence starts with ->begin() and ends with ->end(),
> leaving windows where the suspend/resume sequence is still underway and
> idle code could execute.
>
> The fix is to move the idle disable (disable_hlt) and enable (enable_hlt)
> into ->begin() and ->end() respectively to ensure that the idle path
> is disabled for the entire suspend/resume sequence.
> Remvoving omap3_pm_prepare and omap3_pm_finish since there are now empty.
>
> Tested with RET and OFF on Beagle and OMAP3EVM.
>
> Signed-off-by: Jean Pihet <j-pihet@ti.com>
>
> Comment rework suggested by Kevin.
>
> Cc: Kevin Hilman <khilman@deeprootsystems.com>

Thanks, 

Unless there are any objections, I'll queue for .38 instead of .37-rc
since this isn't technically a regression.

Kevin

> ---
>  arch/arm/mach-omap2/pm34xx.c |   15 ++-------------
>  1 files changed, 2 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 75c0cd1..2e0621e 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -506,12 +506,6 @@ out:
>  #ifdef CONFIG_SUSPEND
>  static suspend_state_t suspend_state;
>  
> -static int omap3_pm_prepare(void)
> -{
> -	disable_hlt();
> -	return 0;
> -}
> -
>  static int omap3_pm_suspend(void)
>  {
>  	struct power_state *pwrst;
> @@ -574,14 +568,10 @@ static int omap3_pm_enter(suspend_state_t unused)
>  	return ret;
>  }
>  
> -static void omap3_pm_finish(void)
> -{
> -	enable_hlt();
> -}
> -
>  /* Hooks to enable / disable UART interrupts during suspend */
>  static int omap3_pm_begin(suspend_state_t state)
>  {
> +	disable_hlt();
>  	suspend_state = state;
>  	omap_uart_enable_irqs(0);
>  	return 0;
> @@ -591,15 +581,14 @@ static void omap3_pm_end(void)
>  {
>  	suspend_state = PM_SUSPEND_ON;
>  	omap_uart_enable_irqs(1);
> +	enable_hlt();
>  	return;
>  }
>  
>  static struct platform_suspend_ops omap_pm_ops = {
>  	.begin		= omap3_pm_begin,
>  	.end		= omap3_pm_end,
> -	.prepare	= omap3_pm_prepare,
>  	.enter		= omap3_pm_enter,
> -	.finish		= omap3_pm_finish,
>  	.valid		= suspend_valid_only_mem,
>  };
>  #endif /* CONFIG_SUSPEND */