[alsa-devel] [PATCH 3/3] ALSA: hda - Disable DigEn bit before stream-id change

[Wang, Xingchao]

> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai at suse.de]
> Sent: Monday, August 13, 2012 4:05 PM
> To: Wang, Xingchao
> Cc: alsa-devel at alsa-project.org
> Subject: Re: [PATCH 3/3] ALSA: hda - Disable DigEn bit before stream-id change
> 
> At Mon, 13 Aug 2012 09:51:33 +0200,
> Takashi Iwai wrote:
> >
> > At Mon, 13 Aug 2012 07:37:12 +0000,
> > Wang, Xingchao wrote:
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Takashi Iwai [mailto:tiwai at suse.de]
> > > > Sent: Monday, August 13, 2012 3:32 PM
> > > > To: Wang, Xingchao
> > > > Cc: alsa-devel at alsa-project.org
> > > > Subject: Re: [PATCH 3/3] ALSA: hda - Disable DigEn bit before
> > > > stream-id change
> > > >
> > > > At Mon, 13 Aug 2012 14:11:11 +0800, Wang Xingchao wrote:
> > > > >
> > > > > Follow the protection way in nvhdmi_8ch_7x_pcm_prepare().
> > > >
> > > > Could you clarify why this is needed?
> > >
> > > > I don't mean an objection, but just need to know if there is any
> > > > other devices that need this fix.  If there really is, better to
> > > > put a bit more details in changelog or comment.
> > >
> > > No, it's not really a fix for the issue.
> > > I just found the change when to investigate HDMI HBR issue and it does
> NOT help fix the issue.
> > > However I thought it's a fix to some other bug(seen from comments),
> > > so I think it's also needed as a common solution. Please correct me if I am
> wrong.
> >
> > I guess this was copied from setup_dig_out_stream() in hda_codec.c.
> > This was a workaround for SPDIF output on some old non-HDMI codecs.
> > But most of recent codecs shouldn't need it.  You see that it's
> > protected by codec->spdif_status_reset check.
> 
> BTW, you might have forgotten to set codec->spdif_status_reset = 1 during
> your test?  Otherwise the code there isn't activated.
> 

Oh, thanks for clarification, will test that again. :)

> Though, this doesn't explain why it worked for nvidia and not for Intel.  The
> IEC958 status temporary toggle code isn't active even for Nvidia, too.
> 

Thanks
--xingchao