[pulseaudio-discuss] module-hal-detect not loading HDMI devices...

[Lennart Poettering]

On Sun, 08.02.09 18:38, Colin Guthrie (gmane at colin.guthr.ie) wrote:

> Hi,
> 
> Someone was asking on IRC as to why module-hal-detect didn't find his 
> HDMI output...

[..]

> In the case of the hdmi output, this is the lowest device number that 
> has the other capabilities we want... should we therefore actually track 
> all devices and only add the one with the lowest number? This would work 
> out as device 0 for most cases but it would also load the HDMI device in 
> this case?

This is almost the same situation as with SPDIF: we have no
information about what the various subdevices of a device actually
refer to. On those creative cards 0,0 is front, 0,1 is rear. On other
cards 0,0 is analog, 0,1 is spdif. On this particular card 0,0 seems
to be analog and, 0,1 hdmi. There are cards where both analog and
spdif is handled through a single device 0,0. Since we have no
information how the subdevices play together we cannot really open
them directly. The only way to properly open them is via the well
defined ALSA device strings. i.e. front:0 will always output to front,
spdif:0 always to spidf and hdmi:0 always to HDMI. This names abstract
how the subdevice mapping actually happens for the specific
driver. This well defined names unfortunately don't carry information
about how they are exclusive to each other.

Given that this is the way it is and it is unlikely ALSA will provide
this "exclusivity" information in near-time future I added a prober to
0.9.15 which will try out all possible combinations of the device
strings and check which ones work simultaneously and which ones
don't. This is then compiled into a single list and made available
through the card profile feature.

Or in shorter words: things aren't so simple as they appear, but SPDIF
and HDMI support has been fixed in 0.9.15.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4