Arch Linux

$nake

Member

Registered: 2014-10-18

Posts: 30

Trouble with Toshiba built-in webcam: "unable to enumerate USB device"

I am running archlinux on a Toshiba Satellite L70-B-12H laptop, and having troubles with the Webcam. *Once in a while*, everything goes well and I get

# lsusb
Bus 004 Device 002: ID 8087:8000 Intel Corp. 
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 004: ID 04f2:b448 Chicony Electronics Co., Ltd 
Bus 003 Device 003: ID 8087:07dc Intel Corp. 
Bus 003 Device 002: ID 8087:8008 Intel Corp. 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

# dmesg
[ 3433.456115] usb 3-1.3: new high-speed USB device number 4 using ehci-pci
[ 3433.781119] media: Linux media interface: v0.10
[ 3433.809842] Linux video capture interface: v2.00
[ 3433.826889] uvcvideo: Found UVC 1.00 device TOSHIBA Web Camera - HD (04f2:b448)
[ 3433.835893] input: TOSHIBA Web Camera - HD as /devices/pci0000:00/0000:00:1a.0/usb3/3-1/3-1.3/3-1.3:1.0/input/input15
[ 3433.835976] usbcore: registered new interface driver uvcvideo
[ 3433.835977] USB Video Class driver (1.1.1)

Unfortunately, *most of the time* the camera seems invisible to my system, and I get

# lsusb
Bus 004 Device 002: ID 8087:8000 Intel Corp. 
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 003: ID 8087:07dc Intel Corp. 
Bus 003 Device 002: ID 8087:8008 Intel Corp. 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

(note the missing "04f2:b448 Chicony Electronics Co., Ltd" device), and

# dmesg
[  480.104252] usb 3-1.3: new full-speed USB device number 4 using ehci-pci
[  480.171097] usb 3-1.3: device descriptor read/64, error -32
[  480.341235] usb 3-1.3: device descriptor read/64, error -32
[  480.511375] usb 3-1.3: new full-speed USB device number 5 using ehci-pci
[  480.578007] usb 3-1.3: device descriptor read/64, error -32
[  480.748151] usb 3-1.3: device descriptor read/64, error -32
[  480.918282] usb 3-1.3: new full-speed USB device number 6 using ehci-pci
[  481.325196] usb 3-1.3: device not accepting address 6, error -32
[  481.392091] usb 3-1.3: new full-speed USB device number 7 using ehci-pci
[  481.798926] usb 3-1.3: device not accepting address 7, error -32
[  481.799166] hub 3-1:1.0: unable to enumerate USB device on port 3

Searching on the web, most results I found lead to this page, where it is said that the problem is due to badly tuned overcurrent protection, and advocated that unplugging and switching off the computer for a little while gets things back into normal. This does not really work for me; the problem seems to occur more randomly, unfortunately with high probability (my camera is available after less than one boot out of ten).

I tried to ensure that the ehci-hcd module is loaded at boot with the ignore-oc option (with a file in /etc/module-load.d/), to no avail.

I also wrote a script which alternatively removes and reloads the ehci-pci driver until my device is found in lsusb. It is sometimes helpful, but usually not. And even when my device is found that way, it can only be used for a while before disappearing again.

Anyway, such a hack is unacceptable... So, my questions are:
is it indeed related to overcurrent protection ?
is there anything else I can try ?
should I file somewhere an other of the numerous bug reports about "unable to enumerate USB device" already existing ?

If of any importance, I am running linux 3.15.7, because at the time I installed my system, I couldn't get the hybrid graphic card Intel/AMD working under 3.16.

Last edited by $nake (2014-10-18 16:29:06)