[alsa-devel] [PATCH] ALSA: hda - Fix a wrong busy check in alt PCM open

[Takashi Iwai]

On Sun, 02 Aug 2015 08:03:25 +0200,
Raymond Yau wrote:
> 
> >
> > Currently, the alt PCM open callback returns -EBUSY when an
> > independent HP is turned off, supposing that it conflicts with the
> > main PCM.  However, obviously, this check is wrong when the
> > independent HP itself isn't enabled but the alt PCM was explicitly
> > created via alc_dac_nid by a codec driver.
> 
> The alt_pcm is created only when indep_hp == 1
> 
> When indep_hp_enable = 0, HP is reconnected to analog device stream , alt
> analog device return ebusy
> 
> This look like bug in indep_hp_possible() which should return false when HP
> and Line Out/Speaker share same DAC

The problem happens in a very special case where the codec driver
enables the alt PCM manually in a fixup.  It doesn't exist in the
current code, so this is no real problem, but just a hypothetical
issue.


Takashi