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

[Takashi Iwai]

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.


Takashi