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Subject[PATCH] Jabra SPEAK 410 USB - no audio playback

The attached patch fixes USB audio support for the Jabra SPEAK 410 USB.

The problem, as I understand it, is that the device contains a
Class-Specific Endpoint (CS_ENDPOINT) descriptor before the Endpoint
(ENDPOINT) descriptor. The USB code all assumes that CS_ENDPOINT can
only appear after ENDPOINT. Therefore the USB code divides up the
interface descriptor into "stuff before ENDPOINT" (in
interface->extra) and "stuff after ENDPOINT" (in
interface->endpoint[0]->extra). For this device, this division does
not work.

You can see lsusb for my device here:
Notice the "** UNRECOGNIZED: 07 25 01 81 02 00 00" line which is the
CS_ENDPOINT descriptor.

The solution (which is a hack ...) is to also search interface->extra
looking for the missing descriptor.

For me, this fully enables the functions of this device.


Richard Jones, Virtualization Group, Red Hat
Read my programming blog:
Fedora now supports 80 OCaml packages (the OPEN alternative to F#)
diff -uNrp kernel-3.1.fc16.orig/sound/usb/stream.c
--- kernel-3.1.fc16.orig/sound/usb/stream.c 2011-12-10 18:03:29.658729051 +0000
+++ 2011-12-10 18:08:41.468694907 +0000
@@ -164,6 +164,12 @@ static int parse_uac_endpoint_attributes

csep = snd_usb_find_desc(alts->endpoint[0].extra, alts->endpoint[0].extralen, NULL, USB_DT_CS_ENDPOINT);

+ /* Jabra SPEAK 410 USB has CS_ENDPOINT before ordinary ENDPOINT,
+ * which confuses the USB descriptor parsing code. Try looking
+ * for CS_ENDPOINT in the interface->extra - RWMJ. */
+ if (!csep)
+ csep = snd_usb_find_desc(alts->extra, alts->extralen, NULL, USB_DT_CS_ENDPOINT);
/* Creamware Noah has this descriptor after the 2nd endpoint */
if (!csep && altsd->bNumEndpoints >= 2)
csep = snd_usb_find_desc(alts->endpoint[1].extra, alts->endpoint[1].extralen, NULL, USB_DT_CS_ENDPOINT);
 \ /
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