[alsa-devel] [PATCH 1/7] ALSA: core: let low-level driver or userspace disable rewinds

[Takashi Iwai]

Hi,

sorry for the late response.  I've been slowly catching up the pending
stuff...

On Mon, 03 Oct 2016 16:39:41 +0200,
Pierre-Louis Bossart wrote:
> 
> 
> >>> @@ -2438,6 +2440,9 @@ static snd_pcm_sframes_t snd_pcm_playback_rewind(struct snd_pcm_substream *subst
> >>>  	if (frames == 0)
> >>>  		return 0;
> >>>
> >>> +	if (runtime->no_rewinds)
> >>> +		return 0;
> >>
> >> Better to return an error instead?
> >
> > As the number of frames rewinded is zero, it looks appropriate. Any reason
> > why returning an error code would help?

Well, this is an operation that is not supposed to work.  The
configuration declares that there shall be no rewind, right?

> The return type is also snd_sframes_t, not sure how a error code would
> be returned without additional changes.

snd_pcm_sframes_t is a signed type, and a negative value is taken as
an error by ioctl.


thanks,

Takashi