| From: Takashi Iwai <tiwai@suse.de> |
| Date: Thu, 25 Apr 2013 07:38:15 +0200 |
| Subject: ALSA: usb-audio: Fix autopm error during probing |
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| 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 SchΓΌrmann <daschuer@mixxx.org> |
| Signed-off-by: Takashi Iwai <tiwai@suse.de> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| sound/usb/card.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/sound/usb/card.c |
| +++ b/sound/usb/card.c |
| @@ -611,7 +611,9 @@ int snd_usb_autoresume(struct snd_usb_au |
| int err = -ENODEV; |
| |
| down_read(&chip->shutdown_rwsem); |
| - if (!chip->shutdown && !chip->probing) |
| + if (chip->probing) |
| + err = 0; |
| + else if (!chip->shutdown) |
| err = usb_autopm_get_interface(chip->pm_intf); |
| up_read(&chip->shutdown_rwsem); |
| |