From: Wolfram Sang <w.sang@pengutronix•de>
To: Anton Vorontsov <avorontsov@ru•mvista.com>
Cc: linuxppc-dev@ozlabs•org, i2c@lm-sensors•org
Subject: Re: [i2c] [PATCH] of/i2c: don't pass -1 to irq_dispose_mapping, otherwise kernel will oops
Date: Sat, 12 Jul 2008 10:22:59 +0200 [thread overview]
Message-ID: <20080712082259.GA16810@pengutronix.de> (raw)
In-Reply-To: <20080711191502.GA21847@polina.dev.rtsoft.ru>
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On Fri, Jul 11, 2008 at 11:15:02PM +0400, Anton Vorontsov wrote:
> > Nope, it was a bug in the i2c documentation fixed recently:
>
> Nope? I'm looking into i2c-core.c:
>
> .. i2c_new_device(...)
> {
> client->irq = info->irq;
>
> Core will blindly pass irq, so clients should ensure that irq contains
> correct value. And as far as there is no common scheme of checking that
> "there is no irq specified", the most safe option is -1.
I wonder if -1 is really the safest; even kernel functions related to
irqs are not consistent if "irq" is int or unsigned int. So, -1 could
cause subtle signedness defects.
The whole "no irq" mess really needs to be cleared generally. It just
disturbed me that i2c_core was imposing -1, whilst some other subsystem
may have chosen 0. IMHO, subsystems like i2c should pass irqs
transparently. This is why I submitted the patch for i2c documentation.
All the best,
Wolfram
--
Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
Pengutronix - Linux Solutions for Science and Industry
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next prev parent reply other threads:[~2008-07-12 8:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 17:48 [PATCH] of/i2c: don't pass -1 to irq_dispose_mapping, otherwise kernel will oops Anton Vorontsov
2008-07-11 18:14 ` Anton Vorontsov
2008-07-11 18:23 ` Grant Likely
2008-07-11 18:55 ` Anton Vorontsov
2008-07-11 19:01 ` Jochen Friedrich
2008-07-11 19:15 ` Anton Vorontsov
2008-07-12 8:22 ` Wolfram Sang [this message]
2008-07-12 8:00 ` [i2c] " Wolfram Sang
2008-07-13 3:59 ` Jon Smirl
2008-07-16 22:20 ` Grant Likely
2008-07-11 19:11 ` Jochen Friedrich
2008-07-11 19:19 ` Anton Vorontsov
2008-07-11 21:18 ` Grant Likely
2008-07-11 21:46 ` Anton Vorontsov
2008-07-11 22:08 ` Grant Likely
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