[alsa-devel] snd-dummy and snd_pcm_new()

[William Juul]

I am using snd-dummy on a NGW100 card with buildroot
provided by Atmel. The alsa version is 1.0.14a and the kernel is
2.6.23.

I have compiled three versions of the snd-dummy driver: the original,
one with capture_count=0 and one
with playback_count=0.
When I use snd_pcm_new() with playback_count=0, there will be no PCM
devices other than the "null" (see below).
Is this expected?
Can I still capture from this driver (and a real driver with the same symptoms)?

Best regards
William Juul

Listings (annotated):

(with original snd-dummy
and
modified snd-dummy to use capture_count=0)

# modprobe snd-dummy
#
# arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]
 Subdevices: 8/8
 Subdevice #0: subdevice #0
 Subdevice #1: subdevice #1
 Subdevice #2: subdevice #2
 Subdevice #3: subdevice #3
 Subdevice #4: subdevice #4
 Subdevice #5: subdevice #5
 Subdevice #6: subdevice #6
 Subdevice #7: subdevice #7
#
# arecord -L
default:CARD=Dummy
   Dummy, Dummy PCM
   Default Audio Device
null
   Discard all samples (playback) or generate zero samples (capture)

# reboot
..
(with modified snd-dummy to use playback_count=0)
# modprobe snd-dummy
# arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
# arecord -L
null
    Discard all samples (playback) or generate zero samples (capture)
#