From mboxrd@z Thu Jan  1 00:00:00 1970
From: nico@fluxnic.net (Nicolas Pitre)
Date: Mon, 19 Dec 2011 18:04:46 -0500 (EST)
Subject: buggy usage of pm_idle by omap1 code
In-Reply-To: <20111219213445.GL14542@n2100.arm.linux.org.uk>
References: <alpine.LFD.2.02.1112162208390.2907@xanadu.home>
 <20111219173518.GH6464@atomide.com>
 <20111219213445.GL14542@n2100.arm.linux.org.uk>
Message-ID: <alpine.LFD.2.02.1112191758520.2907@xanadu.home>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, 19 Dec 2011, Russell King - ARM Linux wrote:

> On Mon, Dec 19, 2011 at 09:35:19AM -0800, Tony Lindgren wrote:
> > 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?

Absolutely.  I must have been stairing at the whole thing for too long, 
as I obviously did exactly that already elsewhere.

So I propose this alternative:

    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.
    
    Replace the NULL assignment in the OMAP1 code with disable_hlt()
    to be in sync with the core code and provide the intended behavior.
    
    Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>

diff --git a/arch/arm/mach-omap1/pm.c b/arch/arm/mach-omap1/pm.c
index 89ea20ca0c..6c6a2dc554 100644
--- a/arch/arm/mach-omap1/pm.c
+++ b/arch/arm/mach-omap1/pm.c
@@ -583,8 +583,6 @@ static void omap_pm_init_proc(void)
 
 #endif /* DEBUG && CONFIG_PROC_FS */
 
-static void (*saved_idle)(void) = NULL;
-
 /*
  *	omap_pm_prepare - Do preliminary suspend work.
  *
@@ -592,8 +590,7 @@ static void (*saved_idle)(void) = NULL;
 static int omap_pm_prepare(void)
 {
 	/* We cannot sleep in idle until we have resumed */
-	saved_idle = pm_idle;
-	pm_idle = NULL;
+	disable_hlt();
 
 	return 0;
 }
@@ -630,7 +627,7 @@ static int omap_pm_enter(suspend_state_t state)
 
 static void omap_pm_finish(void)
 {
-	pm_idle = saved_idle;
+	enable_hlt();
 }