From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: buggy usage of pm_idle by omap1 code
Date: Mon, 19 Dec 2011 21:34:45 +0000 [thread overview]
Message-ID: <20111219213445.GL14542@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20111219173518.GH6464@atomide.com>
On Mon, Dec 19, 2011 at 09:35:19AM -0800, Tony Lindgren wrote:
> Good catch. Here's a patch to deal with that issue, want to take this
> into your idle series? I'll try out your idle series today at some
> point.
Two points:
1. It's good practice to call cpu_idle_wait() after modifying pm_idle,
even on UP - it allows static checking of this.
> From: Tony Lindgren <tony@atomide.com>
> Date: Mon, 19 Dec 2011 09:11:11 -0800
> Subject: [PATCH] ARM: OMAP1: Fix pm_idle during suspend
>
> Commit 9ccdac3662dbf3c75e8f8851a214bdf7d365a4bd ([ARM] idle:
> clean up pm_idle calling, obey hlt_counter) removed a check
> for NULL pm_idle.
>
> On omap1 the system hits an equivalent of suspend during idle.
> If we are suspending, we need to make sure so we don't call
> omap1_pm_idle during the suspend process.
>
> Fix this by setting the pm_idle function to a an empty
> function while suspending.
2. what's wrong with calling disable_hlt() to prevent the pm_idle function
being called? Why solve it this complicated way of changing the pm_idle
pointer when there's some infrastructure which can fix it for you already?
>
> Reported-by: Nicolas Pitre <nico@fluxnic.net>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
>
> diff --git a/arch/arm/mach-omap1/pm.c b/arch/arm/mach-omap1/pm.c
> index 89ea20c..b551a62 100644
> --- a/arch/arm/mach-omap1/pm.c
> +++ b/arch/arm/mach-omap1/pm.c
> @@ -584,6 +584,9 @@ static void omap_pm_init_proc(void)
> #endif /* DEBUG && CONFIG_PROC_FS */
>
> static void (*saved_idle)(void) = NULL;
> +static void omap1_dummy_idle(void)
> +{
> +}
>
> /*
> * omap_pm_prepare - Do preliminary suspend work.
> @@ -593,7 +596,7 @@ static int omap_pm_prepare(void)
> {
> /* We cannot sleep in idle until we have resumed */
> saved_idle = pm_idle;
> - pm_idle = NULL;
> + pm_idle = omap1_dummy_idle;
>
> return 0;
> }
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2011-12-19 21:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-17 3:24 buggy usage of pm_idle by omap1 code Nicolas Pitre
2011-12-19 17:35 ` Tony Lindgren
2011-12-19 17:44 ` Nicolas Pitre
2011-12-19 21:34 ` Russell King - ARM Linux [this message]
2011-12-19 23:04 ` Nicolas Pitre
2011-12-19 23:22 ` Tony Lindgren
2011-12-19 23:20 ` Tony Lindgren
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