From: Anton Vorontsov <avorontsov@ru•mvista.com>
To: Jeff Garzik <jgarzik@pobox•com>, "Steven A. Falco" <sfalco@harris•com>
Cc: linuxppc-dev@ozlabs•org, linux-ide@vger•kernel.org
Subject: [PATCH] pata_of_platform: fix no irq handling
Date: Mon, 11 Aug 2008 19:19:13 +0400 [thread overview]
Message-ID: <20080811151913.GA14690@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <48A05152.7020508@harris.com>
When no irq specified, pata_of_platform fills irq_res with -1,
which is wrong to do for two reasons:
1. By definition, 'no irq' should be IRQ 0, not some negative integer;
2. pata_platform checks for irq_res.start > 0, but since irq_res.start
is unsigned type, the check will be true for `-1'.
Reported-by: Steven A. Falco <sfalco@harris•com>
Signed-off-by: Anton Vorontsov <avorontsov@ru•mvista.com>
---
On Mon, Aug 11, 2008 at 10:48:50AM -0400, Steven A. Falco wrote:
> I think there is a bug in the communications between pata_of_platform
> and pata_platform. I will refer to the master branch of the DENX git
> tree, which is roughly v2.6.26.1 at this time. I am using a Sequoia
> board with a PPC440EPx.
>
> In pata_of_platform, we have:
>
> ret = of_irq_to_resource(dn, 0, &irq_res);
> if (ret == NO_IRQ)
> irq_res.start = irq_res.end = -1;
>
> so if there is no interrupt defined, then start and end are -1.
> However, __pata_platform_probe has:
>
> if (irq_res && irq_res->start > 0) {
> irq = irq_res->start;
> irq_flags = irq_res->flags;
> }
>
> You might think that the (irq_res->start > 0) test will fail, as it
> should in this no-irq case. But, start is a u64, so the -1 actually
> looks like a large positive number in the comparison. So,
> __pata_platform_probe attempts to use an interrupt when there isn't one.
>
> I think the fix would be to change __pata_platform_probe to:
>
> if (irq_res && irq_res->start != -1) {
>
> but that might have other unintended consequences, so I'll defer to
> whomever knows more about the intent of this code.
Something like this patch should work. Thanks for noticing!
drivers/ata/pata_of_platform.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/ata/pata_of_platform.c b/drivers/ata/pata_of_platform.c
index 408da30..1f18ad9 100644
--- a/drivers/ata/pata_of_platform.c
+++ b/drivers/ata/pata_of_platform.c
@@ -52,7 +52,7 @@ static int __devinit pata_of_platform_probe(struct of_device *ofdev,
ret = of_irq_to_resource(dn, 0, &irq_res);
if (ret == NO_IRQ)
- irq_res.start = irq_res.end = -1;
+ irq_res.start = irq_res.end = 0;
else
irq_res.flags = 0;
--
1.5.6.3
next prev parent reply other threads:[~2008-08-11 15:19 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-11 14:48 Possible bug in IRQ handling in pata_of_platform / pata_platform Steven A. Falco
2008-08-11 15:19 ` Anton Vorontsov [this message]
2008-08-11 16:23 ` [PATCH] pata_of_platform: fix no irq handling Steven A. Falco
2008-08-11 17:07 ` Anton Vorontsov
2008-08-11 22:00 ` Benjamin Herrenschmidt
2008-08-12 14:00 ` Steven A. Falco
2008-08-12 14:04 ` Anton Vorontsov
2008-08-12 14:18 ` Stefan Roese
2008-08-12 14:18 ` Sergei Shtylyov
2008-08-12 14:31 ` Anton Vorontsov
2008-08-13 21:25 ` Steven A. Falco
2008-08-11 16:29 ` Alan Cox
2008-08-11 16:36 ` Ben Dooks
2008-08-11 16:26 ` Alan Cox
2008-08-11 16:42 ` Steven A. Falco
2008-08-11 22:02 ` Benjamin Herrenschmidt
-- strict thread matches above, loose matches on Subject: below --
2008-09-25 8:36 [PATCH] pata_platform struct resource signness fix Wang Jian
2008-09-25 8:54 ` Wang Jian
2008-09-25 10:40 ` Li Yang
2008-09-25 10:48 ` Anton Vorontsov
2008-09-29 4:19 ` Jeff Garzik
2008-09-29 13:32 ` [PATCH] pata_of_platform: fix no irq handling Anton Vorontsov
2008-10-06 17:26 Anton Vorontsov
2008-10-06 20:41 ` Matt Sealey
2008-10-06 21:32 ` Anton Vorontsov
2008-10-07 1:30 ` Tejun Heo
2008-10-07 9:18 ` Wang Jian
2008-10-07 9:26 ` Anton Vorontsov
2008-10-07 10:04 ` Benjamin Herrenschmidt
2008-10-07 9:37 ` Alan Cox
2008-10-08 8:40 ` David Woodhouse
2008-10-08 9:00 ` Alan Cox
2008-10-08 9:59 ` Geert Uytterhoeven
2008-10-08 10:27 ` Alan Cox
2008-10-10 17:55 ` Paul Mundt
2008-10-13 6:56 ` Tejun Heo
2008-10-13 23:27 ` Benjamin Herrenschmidt
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