Re: [PATCH v3] OMAP2+: disable idle early in the suspend sequence

[Kevin Hilman <khilman@deeprootsystems.com>]

jean.pihet@newoldbits.com writes:

> From: Jean Pihet <j-pihet@ti.com>
>
> Some bad interaction between the idle and the suspend paths has been
> identified: the idle code is called during the suspend enter and exit
> sequences. This could cause corruption or lock-up of resources.
>
> The solution is to move the calls to disable_hlt at the very beginning
> of the suspend sequence (ex. in omap3_pm_begin instead of
> omap3_pm_prepare), and the call to enable_hlt at the very end of
> the suspend sequence (ex. 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>

OK, one more time... can you Cc linux-arm-kernel as well.

This avoids having to repost to linux-arm-kernel before final merge.
After that, will queue in pm-next for 2.6.38.

Thanks,

Kevin

> ---
> v1:
>  Support for OMAP3 only.
>  Tested on board.
>
> v2:
>  Added support for OMAP2 and OMAP4.
>  Compile tested only for OMAP2 and OMAP4.
>  Tested on board for OMAP3.
>
> v3: 
>  Rebased on Kevin's latest 'OMAP2+: PM/serial: fix console semaphore acquire during suspend', cf. http://marc.info/?l=linux-omap&m=129184804805075&w=2
>  Removed the empty _pm_prepare and _pm_finish functions.
>
>  arch/arm/mach-omap2/pm24xx.c |   16 ++--------------
>  arch/arm/mach-omap2/pm34xx.c |   15 ++-------------
>  arch/arm/mach-omap2/pm44xx.c |   16 ++--------------
>  3 files changed, 6 insertions(+), 41 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm24xx.c b/arch/arm/mach-omap2/pm24xx.c
> index 1e031d0..6cde8ed 100644
> --- a/arch/arm/mach-omap2/pm24xx.c
> +++ b/arch/arm/mach-omap2/pm24xx.c
> @@ -301,14 +301,8 @@ out:
>  
>  static int omap2_pm_begin(suspend_state_t state)
>  {
> -	suspend_state = state;
> -	return 0;
> -}
> -
> -static int omap2_pm_prepare(void)
> -{
> -	/* We cannot sleep in idle until we have resumed */
>  	disable_hlt();
> +	suspend_state = state;
>  	return 0;
>  }
>  
> @@ -349,22 +343,16 @@ static int omap2_pm_enter(suspend_state_t state)
>  	return ret;
>  }
>  
> -static void omap2_pm_finish(void)
> -{
> -	enable_hlt();
> -}
> -
>  static void omap2_pm_end(void)
>  {
>  	suspend_state = PM_SUSPEND_ON;
> +	enable_hlt();
>  	return;
>  }
>  
>  static struct platform_suspend_ops omap_pm_ops = {
>  	.begin		= omap2_pm_begin,
> -	.prepare	= omap2_pm_prepare,
>  	.enter		= omap2_pm_enter,
> -	.finish		= omap2_pm_finish,
>  	.end		= omap2_pm_end,
>  	.valid		= suspend_valid_only_mem,
>  };
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 648b8c5..5bf344a 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -529,12 +529,6 @@ out:
>  }
>  
>  #ifdef CONFIG_SUSPEND
> -static int omap3_pm_prepare(void)
> -{
> -	disable_hlt();
> -	return 0;
> -}
> -
>  static int omap3_pm_suspend(void)
>  {
>  	struct power_state *pwrst;
> @@ -597,14 +591,10 @@ 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;
> @@ -614,15 +604,14 @@ 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 */
> diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
> index 54544b4..6aff996 100644
> --- a/arch/arm/mach-omap2/pm44xx.c
> +++ b/arch/arm/mach-omap2/pm44xx.c
> @@ -31,12 +31,6 @@ struct power_state {
>  static LIST_HEAD(pwrst_list);
>  
>  #ifdef CONFIG_SUSPEND
> -static int omap4_pm_prepare(void)
> -{
> -	disable_hlt();
> -	return 0;
> -}
> -
>  static int omap4_pm_suspend(void)
>  {
>  	do_wfi();
> @@ -59,28 +53,22 @@ static int omap4_pm_enter(suspend_state_t suspend_state)
>  	return ret;
>  }
>  
> -static void omap4_pm_finish(void)
> -{
> -	enable_hlt();
> -	return;
> -}
> -
>  static int omap4_pm_begin(suspend_state_t state)
>  {
> +	disable_hlt();
>  	return 0;
>  }
>  
>  static void omap4_pm_end(void)
>  {
> +	enable_hlt();
>  	return;
>  }
>  
>  static struct platform_suspend_ops omap_pm_ops = {
>  	.begin		= omap4_pm_begin,
>  	.end		= omap4_pm_end,
> -	.prepare	= omap4_pm_prepare,
>  	.enter		= omap4_pm_enter,
> -	.finish		= omap4_pm_finish,
>  	.valid		= suspend_valid_only_mem,
>  };
>  #endif /* CONFIG_SUSPEND */