[alsa-devel] Question about the right fix for a sparse warning

[Pierre-Louis Bossart]

>>>> We're seeing the following sparse warning in the SOF code:
>>>>
>>>> sound/soc/sof/sof-audio.c:86:31: warning: incorrect type in assignment (different base types)
>>>> sound/soc/sof/sof-audio.c:86:31:    expected restricted snd_pcm_state_t [usertype] state
>>>> sound/soc/sof/sof-audio.c:86:31:    got signed int [signed] [usertype] [explicitly-signed] state
>>>>
>>>> The line under scrutiny where we assign "state" is as follows:
>>>>
>>>> state = substream->runtime->status->state;
>>>>
>>>> and it is defined as
>>>> snd_pcm_state_t state;
>>>>
>>>> There are other places (ex pcm_oss.c) where a similar assignment has been used
>>>> as well.
>>>>
>>>> What fixes the issue is a forced cast to snd_pcm_state_t as below before
>>>> assigning:
>>>>    state = (__force snd_pcm_state_t)substream->runtime->status->state;
>>>>
>>>> Do you think this is acceptable? If not, could you please suggest an
>>>> alternative?
>>>
>>> Hm, I don't see the warning in my code.  Did you merge all upstream
>>> stuff and still get it?
>>
>> It's been merged in the SOF tree (topic/sof-dev) and it'll be in the
>> next batch I send. It's not upstream just yet because we want to
>> remove the warning to make the patch nice and shiny :-)
> 
> I still wonder why I couldn't get it on my tree.  I guess the code
> around that hasn't changed, right?
> 
> Wait...  Is it a test on 32bit arch?  If so, it might be a new thing
> for y2038 support.  Then we may fix the uapi definition instead.

It's actually in your tree already, my mistake, see:

ee1e79b72e3cf ("ASoC: SOF: partition audio-related parts from SOF core")

It's with plain-vanilla x86_64, I can share the config.