RE: [PATCH] OMAP3: disable idle early in the suspend sequence

[Rajendra Nayak <rnayak@ti.com>]

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org
[mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Jean Pihet
> Sent: Monday, November 22, 2010 4:15 PM
> To: linux-omap@vger.kernel.org
> Cc: Jean Pihet; Kevin Hilman
> Subject: [PATCH] OMAP3: disable idle early in the suspend sequence
>
> Some bad interaction between the idle and the suspend paths has been
> noticed: the idle code is called during the suspend enter and exit
> sequences. This could cause corruption or lock-up of resources.

Can you elaborate more on what kind of issues were seen?

>
> The solution is to move the call to disable_hlt at the very beginning
> of the suspend sequence (in omap3_pm_begin instead of omap3_pm_prepare),
> and the call to enable_hlt at the very end of the suspend sequence
> (in omap3_pm_end instead of omap3_pm_finish).
>
> Tested with RET and OFF on Beagle and OMAP3EVM.
>
> Signed-off-by: Jean Pihet <j-pihet@ti.com>
> Cc: Kevin Hilman <khilman@deeprootsystems.com>
> ---
>  arch/arm/mach-omap2/pm34xx.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 75c0cd1..022fdff 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -508,7 +508,6 @@ static suspend_state_t suspend_state;
>
>  static int omap3_pm_prepare(void)
>  {
> -	disable_hlt();
>  	return 0;
>  }
>
> @@ -576,12 +575,12 @@ static int omap3_pm_enter(suspend_state_t unused)
>
>  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;
> @@ -591,6 +590,7 @@ static void omap3_pm_end(void)
>  {
>  	suspend_state = PM_SUSPEND_ON;
>  	omap_uart_enable_irqs(1);
> +	enable_hlt();
>  	return;
>  }
>
> --
> 1.7.2.3
>
> --
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