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| author | Clemens Ladisch <clemens@ladisch.de> | 2009-07-13 13:21:58 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2009-07-15 11:55:00 +0200 |
| commit | 8886f33f25083a47d5fa24ad7b57bb708c5c5403 (patch) | |
| tree | 6f6e50f07811c01cd7ec469223ba70fb71ae50f6 /sound/usb/usbaudio.c | |
| parent | 6847e154e3cd74fca6084124c097980a7634285a (diff) | |
| download | linux-8886f33f25083a47d5fa24ad7b57bb708c5c5403.tar.gz linux-8886f33f25083a47d5fa24ad7b57bb708c5c5403.tar.bz2 linux-8886f33f25083a47d5fa24ad7b57bb708c5c5403.zip | |
sound: usb-audio: add workaround for Blue Microphones devices
Blue Microphones USB devices have an alternate setting that sends two
channels of data to the computer. Unfortunately, the descriptors of
that altsetting have a wrong channel setting, which means that any
recorded data from such a device has twice the sample rate from what
would be expected.
This patch adds a workaround to ignore that altsetting. Since these
devices have only one actual channel, no data is lost.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/usbaudio.c')
| -rw-r--r-- | sound/usb/usbaudio.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/sound/usb/usbaudio.c b/sound/usb/usbaudio.c index c7b902358b7b..44b9cdc8a83b 100644 --- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -2661,7 +2661,7 @@ static int parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no) struct usb_interface_descriptor *altsd; int i, altno, err, stream; int format; - struct audioformat *fp; + struct audioformat *fp = NULL; unsigned char *fmt, *csep; int num; @@ -2734,6 +2734,18 @@ static int parse_audio_endpoints(struct snd_usb_audio *chip, int iface_no) continue; } + /* + * Blue Microphones workaround: The last altsetting is identical + * with the previous one, except for a larger packet size, but + * is actually a mislabeled two-channel setting; ignore it. + */ + if (fmt[4] == 1 && fmt[5] == 2 && altno == 2 && num == 3 && + fp && fp->altsetting == 1 && fp->channels == 1 && + fp->format == SNDRV_PCM_FORMAT_S16_LE && + le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize) == + fp->maxpacksize * 2) + continue; + csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT); /* Creamware Noah has this descriptor after the 2nd endpoint */ if (!csep && altsd->bNumEndpoints >= 2) |