[alsa-devel] [PATCH 1/2] ALSA: update sync header when streams are linked/unlinked
tiwai at suse.de
Fri May 25 07:54:29 CEST 2012
At Wed, 23 May 2012 13:57:34 -0500,
Pierre-Louis Bossart wrote:
> > Also, the point of the sync id is that it's shared with all linked
> > streams. Your patch breaks it. It updates only the last added sync
> > id.
> > The fact that the driver currently sets only the card number is
> > actually problematic. It's not unique enough. This should be fixed.
> > But, exposing the substream bitmask doesn't help much because it can't
> > be fully implemented in the sync id size. If you need to know which
> > streams are linked, loop over all streams and check the sync id.
> If I understand you well, the sync id should be a unique identifier
> shared by all linked streams in the same group. Since devices can be
> linked/unlinked, this id cannot use anything related to device or
> subdevice number. Maybe a pid-like value incremented when a group is
> created would do?
Yes, that sounds like a reasonable solution.
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