[alsa-devel] [ALSA patch] [PATCH 1/2] alsa: pcm: add unsupported OPS

[Miartus, Adam (Arion Recruitment; ADITG/ESM)]

> -----Original Message-----
> From: Takashi Iwai <tiwai at suse.de>
> Sent: Dienstag, 9. Juli 2019 14:25
> To: Miartus, Adam (Arion Recruitment; ADITG/ESM) <amiartus at de.adit-
> jv.com>
> Cc: alsa-devel at alsa-project.org; Pape, Andreas (ADITG/ESS1)
> <apape at de.adit-jv.com>
> Subject: Re: [ALSA patch] [PATCH 1/2] alsa: pcm: add unsupported OPS
> 
> On Mon, 08 Jul 2019 13:04:48 +0200,
> Adam Miartus wrote:
> >
> > From: Andreas Pape <apape at de.adit-jv.com>
> >
> > Signed-off-by: Andreas Pape <apape at de.adit-jv.com>
> > Signed-off-by: Adam Miartus <amiartus at de.adit-jv.com>
> 
> No description isn't good at all.  There must be something you can
> explain in details here.

Certainly, I will add explanation in patch v2.

> 
> About the changes:
> 
> > +#define PCM_UNSUPPORTED_ERR (-ENOSYS)
> > +void snd_pcm_unsupported_dump(snd_pcm_t *pcm, snd_output_t
> *out)
> > +{
> > +	snd_output_printf(out, "unsupported\n");
> > +}
> 
> IMO, we don't need to show anything if it's dummy.
> And, maybe it's more straightforward to let the PCM core allow NULL
> ops?
> 

If you agree I could add following in patch v2, then we could drop snd_pcm_unsupported_dump function altogether

diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c
index e0ceccc..4d91d4d 100644
--- a/src/pcm/pcm.c
+++ b/src/pcm/pcm.c
@@ -2277,7 +2277,8 @@ int snd_pcm_dump(snd_pcm_t *pcm, snd_output_t *out)
 {
        assert(pcm);
        assert(out);
-       pcm->ops->dump(pcm->op_arg, out);
+       if (pcm->ops->dump)
+               pcm->ops->dump(pcm->op_arg, out);
        return 0;
 }

Please let me know if you agree with proposed changes and I will prepare patch v2.

Adam