Re: [PATCH v5 00/17] ASoC: fsl_ssi: Clean up - program flow level
From: Maciej S. Szmigiero
Date: Wed Jan 17 2018 - 15:28:17 EST
On 17.01.2018 21:02, Nicolin Chen wrote:
> On Wed, Jan 17, 2018 at 08:38:48PM +0100, Maciej S. Szmigiero wrote:
>
>> However, I have a small nitpick regarding a comment newly added in
>> this version of patch 16:
>> + /*
>> + * Do not set SSI dev as the parent of AC97 CODEC device since
>> + * it does not have a DT node. Otherwise ASoC core will assume
>> + * CODEC has the same DT node as the SSI, so it may return a
>> + * NULL pointer of CODEC when asked for SSI via the DT node
>>
>> The second part of the last sentence isn't really true, the ASoC core
>> will return a (valid, non-NULL) CODEC object pointer when asked for
>> the SSI one if we set the SSI as the parent device of a AC'97 CODEC
>> platform device.
>>
>> The NULL pointer dereference when starting a playback that I wrote
>> about in my previous message happens because in this situation the SSI
>> DAI probe callback won't ever get called and so won't setup DMA data
>> pointers (they will remain NULL).
>
> Well, somehow the DMA data pointer of CODEC could be described
> as "a NULL pointer of CODEC" reluctantly...it confuses people
> though.
>
>> And this in turn will cause the ASoC DMA code to dereference these
>> NULL pointers when starting a playback (the same will probably happen
>> also when starting a capture).
>>
>> Sorry if I wasn't 100% clear about these details in my previous
>> message describing this issue.
>
> I would prefer to send an incremental patch later to update it,
> if there are no new comments against this version; Otherwise, I
> will update it in a next version once there is a need to send a
> v6 anyway.
IMHO it is such a tiny thing that it isn't worth respinning 17
patch series just for it, it can be easily improved later via
a separate patch.
> Thanks
>
Thanks,
Maciej