ALSA: usb-audio: Fix autopm error during probing
authorTakashi Iwai <tiwai@suse.de>
Thu, 25 Apr 2013 05:38:15 +0000 (07:38 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 8 May 2013 02:51:55 +0000 (19:51 -0700)
commit8a70ddb052fe8b95e31d76a940e48838bc6dc991
treea5432f96a173c7bfb9194f377bcb1e5ca46a9473
parentb01ae289a30eb22f54d64951032f2a2b1d6bd532
ALSA: usb-audio: Fix autopm error during probing

commit 60af3d037eb8c670dcce31401501d1271e7c5d95 upstream.

We've got strange errors in get_ctl_value() in mixer.c during
probing, e.g. on Hercules RMX2 DJ Controller:

  ALSA mixer.c:352 cannot get ctl value: req = 0x83, wValue = 0x201, wIndex = 0xa00, type = 4
  ALSA mixer.c:352 cannot get ctl value: req = 0x83, wValue = 0x200, wIndex = 0xa00, type = 4
  ....

It turned out that the culprit is autopm: snd_usb_autoresume() returns
-ENODEV when called during card->probing = 1.

Since the call itself during card->probing = 1 is valid, let's fix the
return value of snd_usb_autoresume() as success.

Reported-and-tested-by: Daniel Schürmann <daschuer@mixxx.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sound/usb/card.c