[alsa-devel] [PATCH] Fix codec_dai->ops NULL pointer bug for AC97 codec dai in soc-core

Barry Song 21cnbao at gmail.com
Fri Oct 16 11:35:12 CEST 2009

On Fri, Oct 16, 2009 at 5:32 PM, Mark Brown
<broonie at opensource.wolfsonmicro.com> wrote:
> On Fri, Oct 16, 2009 at 05:14:31PM +0800, Barry Song wrote:
>> On Fri, Oct 16, 2009 at 5:08 PM, Mark Brown
>> > This is the wrong fix - null DAI ops are supposed to be supported for
>> > all devices since not all DAIs will be configurable.
>> But the problem is ac97 DAIs will have no path to get the null ops.
>> Then many functions will panic. It's very easy to repeat the problem
>> in your site, only by deleting ops field in any AC97 codec DAI.
> Sure, I see the problem.  The issue is that this could affect any CODEC,
> not just AC97 ones, so an AC97-specific fix isn't what's needed.  Given
> the idiom of the rest of the code the best thing would be to make all
> the remaining callers check for ops before dereferencing it.
At the beginning, I wanted to do like this. But I saw all other codec
DAIs register themselves, then got a null ops. Just ac97 is forgot.
Then I patched AC97 codec DAIs.
Then you prefer to patch all ops access?


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