On Tue, Mar 18, 2008 at 04:11:17PM +0100, cklein@mpi-sb.mpg.de wrote:
Hi,
I recently got a Plantronics .audio 910 USB headset. It is correctly detected by snd-usb-audio and works, but I cannot change the volume of the PCM output or the MIC input. When executing alsamixer -c 1, the volumes seem to be locked and cannot be changed as usual. Unfortunately the microphone volume is at 0, leading to very poor quality of the recorded voice (especially in Skype, which seems to try to compensate the low volume and fails miserably). Does anyone know how to fix this? I found similar reports on the internet for various usb headsets, but no real fix for the situation. I already asked on alsa-users some weeks ago, but did not get any response.
I tried the headset on three different PCs, all with the same result. A desktop at work running Fedora 7, a Thinkpad R50p running debian/testing and the 2.6.22 kernel provided in debian/testing. The third one is a Dell precision M65 with debian/unstable. There, I used a vanilla 2.6.24.2 kernel and latest alsa drivers from the mercurial repository when I asked on alsa-users, but in the meantime I upgraded to 2.6.24.3 and hg snapshots from 2008-03-13 06:41 (alsa-driver) and 2008:03:17 05:23 (alsa-kernel), but still got the same behaviour. On all I get some message about "no or invalid class specific endpoint descriptor" in the kernel log (see below). When loading the snd-usb-audio module, dmesg shows the following kernel output (on the M65):
usb 2-2: new full speed USB device using uhci_hcd and address 5 usb 2-2: configuration #1 chosen from 1 choice input: Plantronics Plantronics BT Adapter as /devices/pci0000:00/0000:00:1d.1/usb2/2-2/2-2:1.3/input/input10 input: USB HID v1.11 Device [Plantronics Plantronics BT Adapter] on usb-0000:00:1d.1-2 usbcore: registered new interface driver usbhid drivers/hid/usbhid/hid-core.c: v2.6:USB HID core driver ALSA /usr/src/kernel-modules/alsa-driver-d20080313_0641-k20080317_0523/usb/usbaudio.c:2787: 5:1:1 : no or invalid class specific endpoint descriptor ALSA /usr/src/kernel-modules/alsa-driver-d20080313_0641-k20080317_0523/usb/usbaudio.c:2787: 5:2:1 : no or invalid class specific endpoint descriptor usbcore: registered new interface driver snd-usb-audio
I posted the output of alsa-info.sh and lsusb -v on pastebin (both taken on the M65).
alsa-info.sh: http://pastebin.ca/915715 lsusb -v: http://pastebin.ca/915723
Does no one have a clue what could be the cause for this behaviour? If I boot windows, the headset works flawlessly. Unfortunately I have no clue what could be wrong or where else to find information about this problem.