[Gta04-owner] 3.2-gta04 updated - improved CPUIDLE

[NeilBrown]

On Thu, 26 Jan 2012 16:12:32 +0100 Radek Polak <psonek2 at seznam.cz> wrote:

> >  I don't know if this will have affected the problem with touchscreen input
> >  getting lost - testing and feedback there is most welcome.
> 
> No, the problem still remains.

I just noticed the following email on the linux-omap list.

It suggests that:

diff --git a/arch/arm/mach-omap2/board-omap3gta04.c b/arch/arm/mach-omap2/board-omap3gta04.c
index 6e14d2c..082a0e2 100644
--- a/arch/arm/mach-omap2/board-omap3gta04.c
+++ b/arch/arm/mach-omap2/board-omap3gta04.c
@@ -878,7 +878,7 @@ static int __init tsc2007_init(void)
 			   "input\n", TS_PENIRQ_GPIO);
 		return -ENXIO;
 	}
-	gpio_set_debounce(TS_PENIRQ_GPIO, (0x0a+1)*31);
+//	gpio_set_debounce(TS_PENIRQ_GPIO, (0x0a+1)*31);
 	irq_set_irq_type(OMAP_GPIO_IRQ(TS_PENIRQ_GPIO), IRQ_TYPE_EDGE_FALLING);
 	return 0;
 }

might fix this problem.  Or at least change it.

The debounce function requires a clock to be active, and the clock is
currently being turned off in idle.

It's probably best to keep the clock off to save power.  I wonder how
important the debounce is though....

(patch it totally untested).

NeilBrown

From: Kevin Hilman <khilman at ti.com>
To: Grazvydas Ignotas <notasas at gmail.com>
Cc: linux-omap at vger.kernel.org, Paul Walmsley <paul at pwsan.com>
Subject: Re: GPIO debounce problems on 3.2
Date: Mon, 30 Jan 2012 11:36:04 -0800
Sender: linux-omap-owner at vger.kernel.org
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux)
Organization: Texas Instruments, Inc.

Grazvydas Ignotas <notasas at gmail.com> writes:

> Hi,
>
> On 3.2 (I think some earlier versions too), with CONFIG_CPU_IDLE
> enabled GPIO based buttons are not working properly on OMAP3 pandora,
> button presses are almost never registered. The buttons are connected
> GPIO bank4 and have hardware debounce feature enabled.
>
> Doing either of the following solves (or hides) the problem:
> - disabling CPU_IDLE in kernel config
> - disabling debounce for the buttons
> - running a program spinning a loop on the CPU
>
> From what I can see in the code debounce clock is disabled when
> entering idle, can those GPIOs work without debounce clock?  

Yes, the clock is only for the debounce feature, but the GPIOs are
capable of wakeups and interrupts with the debounce clock disabled.

Kevin
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