Messages in this thread Patch in this message | | | Date | Tue, 28 Jul 2009 16:40:33 -0700 | From | Greg KH <> | Subject | [patch 04/71] sound: usb-audio: add workaround for Blue Microphones devices |
| |
2.6.30-stable review patch. If anyone has any objections, please let us know.
------------------
From: Clemens Ladisch <clemens@ladisch.de>
commit 8886f33f25083a47d5fa24ad7b57bb708c5c5403 upstream.
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> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- sound/usb/usbaudio.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
--- a/sound/usb/usbaudio.c +++ b/sound/usb/usbaudio.c @@ -2649,7 +2649,7 @@ static int parse_audio_endpoints(struct 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; @@ -2722,6 +2722,18 @@ static int parse_audio_endpoints(struct 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)
| |