[PATCH] OMAP3: PM: ensure IO wakeups are properly disabled

[PATCH] OMAP3: PM: ensure IO wakeups are properly disabled

[Kevin Hilman]

From: Kevin Hilman <khilman@ti.com>

During idle, if the PER powerdomain transitions and CORE does not (as
is the case with the lower C-states when using CPUidle) the IO pad
wakeups are not being disabled in the idle path after they are
enabled.

This patch ensures that the check for disabling IO wakeups also checks
for PER transitions, matching the check done to enable IO wakeups.

Found when debugging PM/CPUidle related problems reported by Ameya
Palande <ameya.palande@nokia.com>.  Problems were triggered
particularily on boards with UART2 consoles (n900, Overo) since UART2
is in the PER powerdomain.

Tested on l-o master (omap3_defonfig + CONFIG_CPU_IDLE=y) as well
as with current PM branch.  Boards tested: n900, Overo, omap3evm.

Cc: Ameya Palande <ameya.palande@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
---
This should go into 2.6.36-rc2 as it's a fix for a serious regression.

 arch/arm/mach-omap2/pm34xx.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index fb4994a..7b03426 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -480,7 +480,9 @@ void omap_sram_idle(void)
 	}
 
 	/* Disable IO-PAD and IO-CHAIN wakeup */
-	if (omap3_has_io_wakeup() && core_next_state < PWRDM_POWER_ON) {
+	if (omap3_has_io_wakeup() &&
+	    (per_next_state < PWRDM_POWER_ON ||
+	     core_next_state < PWRDM_POWER_ON)) {
 		prm_clear_mod_reg_bits(OMAP3430_EN_IO_MASK, WKUP_MOD, PM_WKEN);
 		omap3_disable_io_chain();
 	}
-- 
1.7.2.1

Re: [PATCH] OMAP3: PM: ensure IO wakeups are properly disabled

[Jarkko Nikula]

On Tue, 10 Aug 2010 16:53:51 -0700
Kevin Hilman <khilman@deeprootsystems.com> wrote:

> From: Kevin Hilman <khilman@ti.com>
> 
> During idle, if the PER powerdomain transitions and CORE does not (as
> is the case with the lower C-states when using CPUidle) the IO pad
> wakeups are not being disabled in the idle path after they are
> enabled.
> 
> This patch ensures that the check for disabling IO wakeups also checks
> for PER transitions, matching the check done to enable IO wakeups.
> 
> Found when debugging PM/CPUidle related problems reported by Ameya
> Palande <ameya.palande@nokia.com>.  Problems were triggered
> particularily on boards with UART2 consoles (n900, Overo) since UART2
> is in the PER powerdomain.
> 
> Tested on l-o master (omap3_defonfig + CONFIG_CPU_IDLE=y) as well
> as with current PM branch.  Boards tested: n900, Overo, omap3evm.
> 
> Cc: Ameya Palande <ameya.palande@nokia.com>
> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
> ---

I don't see the problem on N900 anymore after applying this patch. Feel
free to add:

Tested-by: Jarkko Nikula <jhnikula@gmail.com>