src/conf/cards: Add missing entry for Loopback.conf

Signed-off-by: Takashi Iwai <tiwai@suse.de>
pcm: route: Don't handle no matching chmap as a serious error

When find_matching_chmap() returns an error for the non-matching
chmap, the caller, snd_pcm_route_open(), also returns an error
although it shouldn't be handled as the fatal error.  This results in
the probe error with PulseAudio and it gives no real output in the
end.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
route: Return NULL in case of zero found channels in determine_chmap

This should fix the problem where the old route syntax can no longer
be opened.

Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
route: Fix invalid pointer access

An uninitialized chmap pointer value is assigned in
_snd_pcm_route_open().  Add NULL initializations appropriately, and
also avoid the possible invalid access of NULL pcmp pointer.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Revert "pcm: route: Don't handle no matching chmap as a serious error"

This reverts commit 5b72e3d5305930bffc300aa4f2545ba95992c144.

With the previous fixes, it's no longer needed as a workaround for
regression with PulseAudio.

Signed-off-by: Takashi Iwai <tiwai@suse.de>