[PATCHv2] at91: fix enable/disable_irq_wake symmetry in pcmcia driver

[PATCHv2] at91: fix enable/disable_irq_wake symmetry in pcmcia driver

[Marc Pignat]

from Marc Pignat <marc.pignat@hevs.ch>

fix enable_irq_wake and disable_irq_wake symmetry in at91 pcmcia driver

Signed-off-by: Marc Pignat <marc.pignat@hevs.ch>
---
Please forget the [PATCH] at91: fix enable/disable_irq_wake symmetry in pcmcia driver,
it doesn't compile... Here is the good patch!

This patch applies to the 2.6.21.1 kernel.

disable_irq_wake call must be symmetric with enable_irq_wake. This patch fix 
that problem for the at91_pcmia driver.
It seems that this patch was forgotten when we've fixed irq_wake symmetry in 
all at91 related drivers.
It was discussed in the "at91 drivers and [enable/disable]_irq_wake (wrong?) 
usage" thread on the linux-arm-kernel mailing list.

Regards

Marc

--- 2.6.21.1/drivers/pcmcia/at91_cf.c.orig	2007-05-10 08:43:16.000000000 +0200
+++ 2.6.21.1/drivers/pcmcia/at91_cf.c	2007-05-10 10:03:58.000000000 +0200
@@ -336,16 +336,21 @@ static int at91_cf_suspend(struct platfo
 		enable_irq_wake(board->det_pin);
 		if (board->irq_pin)
 			enable_irq_wake(board->irq_pin);
-	} else {
-		disable_irq_wake(board->det_pin);
-		if (board->irq_pin)
-			disable_irq_wake(board->irq_pin);
 	}
 	return 0;
 }

 static int at91_cf_resume(struct platform_device *pdev)
 {
+	struct at91_cf_socket	*cf = platform_get_drvdata(pdev);
+	struct at91_cf_data	*board = cf->board;
+
+	if (device_may_wakeup(&pdev->dev)) {
+		disable_irq_wake(board->det_pin);
+		if (board->irq_pin)
+			disable_irq_wake(board->irq_pin);
+	}
+
 	pcmcia_socket_dev_resume(&pdev->dev);
 	return 0;
 }

Re: [PATCHv2] at91: fix enable/disable_irq_wake symmetry in pcmcia driver

[Andrew Morton]

On Thu, 10 May 2007 10:09:35 +0200
Marc Pignat <marc.pignat@hevs.ch> wrote:

> from Marc Pignat <marc.pignat@hevs.ch>
> 
> fix enable_irq_wake and disable_irq_wake symmetry in at91 pcmcia driver
> 
> Signed-off-by: Marc Pignat <marc.pignat@hevs.ch>
> ---
> Please forget the [PATCH] at91: fix enable/disable_irq_wake symmetry in pcmcia driver,
> it doesn't compile... Here is the good patch!
> 
> This patch applies to the 2.6.21.1 kernel.
> 
> disable_irq_wake call must be symmetric with enable_irq_wake. This patch fix 
> that problem for the at91_pcmia driver.
> It seems that this patch was forgotten when we've fixed irq_wake symmetry in 
> all at91 related drivers.
> It was discussed in the "at91 drivers and [enable/disable]_irq_wake (wrong?) 
> usage" thread on the linux-arm-kernel mailing list.


That's not a terribly useful changelog, sorry.  I look at the patch and I
don't know what was wrong with the old code, nor how this new code improves
things.

"disable_irq_wake call must be symmetric with enable_irq_wake".  hmm, OK,
I'll take your word for it.

Does the present code actually fail in some manner, or what?

Re: [PATCHv2] at91: fix enable/disable_irq_wake symmetry in pcmcia driver

[David Brownell]

On Thursday 10 May 2007, Andrew Morton wrote:

> "disable_irq_wake call must be symmetric with enable_irq_wake".  hmm, OK,
> I'll take your word for it.

In the same way that enable_irq() and disable_irq() must be matched,
and for the same reasons:  when the IRQ is shared between drivers,
they can't all treat enable/disable status as boolean.  Those calls
mask refcountig.


> Does the present code actually fail in some manner, or what?

Yes ... runtime warnings flagging various misbehaviors associated
with refcount mismatches.

- Dave