On 19. 09. 22 13:33, Kai Vehmanen wrote:
Hi,
sorry for the late review (as Takashi already applied).
On Tue, 13 Sep 2022 09:02:16 +0200, Jaroslav Kysela wrote:
When the user space pcm stream uses the silent stream converter, it is no
longer allocated for the silent stream. Clear the appropriate flag in the
hdmi_pcm_open() function. The silent stream setup may be applied in
hdmi_pcm_close() (and the error path - open fcn) again.
Jaroslav, did you hit a real-life problem with a particular sequence? The
converter allocation was done in a sticky fashion on purpose. The silent
stream setup (clearing KAE and/or letting codec to power down) was only
released if the receiver is disconnected from the system. I.e. no actions
were done in PCM close (on purpose).
Thank you for your comments.
I just wrote a small test utility which shows the bad converter use:
https://gist.github.com/perexg/4977fcb33101148e578c34bd25db8ce4
For the first use (with one monitor connected) I can open 4 HDMI PCM devices,
but later, only 3 HDMI PCM devices can be opened, because the converter
allocation code (3 converters in my case) does a wrong job.
I though that the silent stream is turned off when new S/PDIF frame parameters
are applied, but it seems that this setup is independent as you noted.
Now if there were issues, I wonder whether we should modify the pcm_close
instead, and avoid some of the cleanup in this case, as a better fix.
Yes, I think that we should add a new silent_stream flag to struct
hdmi_spec_per_cvt and do not set assigned in this struct when the silent
stream is managed. The assigned flag should be used only for open/close calls
to track the used converters correctly. Does it sound right for you?
I think your patch will create a new problem: - receiver A connected to CVT
X - silent stream enabled for X - app opens a PCM, connected to A+X, silent
stream disabled - receiver A disconnected -> actions in
silent_stream_disable() not run correctly for CVT X
Definitely. The silent stream setup won't be deactivated with this simple patch.
Jaroslav
--
Jaroslav Kysela <perex@xxxxxxxx>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
