Webcam not Detected in /dev

ierosvin · 01-18-2011, 03:05 AM

Hello,

i have this new laptop. but cant find the built-in camera in /dev/.

i tried the ff:

Code:

$lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 5986:0241 Acer, Inc
Bus 001 Device 003: ID 0bda:8189 Realtek Semiconductor Corp. RTL8187B Wireless 802.11g 54Mbps Network Adapter
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

my webcam is being detected correctly as Bus 001 Device 002: ID 5986:0241 Acer, Inc.

also i tried:

Code:

$lsusb -v

and i noticed that it is listed in /dev/bus/usb/001/ as 002. i dont know what this means.
i expected the webcam to be listed in /dev as video0.

other info:

Code:

$lsmod | grep video
uvcvideo               45415  0
videodev               26099  1 uvcvideo
v4l1_compat            10806  2 uvcvideo,videodev
i2c_core               12093  1 videodev
usbcore                91985  5 rtl8187,uvcvideo,ohci_hcd,ehci_hcd
video                  15391  0
output                  1224  1 video
thermal_sys             9782  3 thermal,video,processor

in other systems, we can

Code:

$cat /dev/video0 > test.jpg

and this is what im trying to do with my webcam. so that, hopefully, i can access my webcam using IOCTL.

help please.

thanks in advance.

cin_ · 01-18-2011, 04:24 AM

Yeah, I have an AcerAOD250, and my builtin cam shows as usb.
It seems strange, but there is nothing nefarious here.

Rhetorical it is just silly to have a Universal port with a dedicated connection. Its universality being unnecessary...
But, perhaps is was cost or resource effective to use an USB port for the camera.

Code:

# lsusb | grep cam
Bus 001 Device 002: ID 064e:d101 Suyin Corp. Acer CrystalEye Webcam
# dmesg | grep uvc
uvcvideo: Found UVC 1.00 device WebCam (064e:d101)
usbcore: registered new interface driver uvcvideo
# v4l2-ctl --all 
Driver Info:
	Driver name   : uvcvideo
	Card type     : WebCam
	Bus info      : usb-0000:00:1d.7-2
	Driver version: 256
	Capabilities  : 0x04000001
		Video Capture
		Streaming
Format Video Capture:
	Width/Height  : 320/240
	Pixel Format  : 'YUYV'
	Field         : None
	Bytes per Line: 640
	Size Image    : 153600
	Colorspace    : Unknown (00000000)
Crop Capability Video Capture:
	Bounds      : Left 0, Top 0, Width 320, Height 240
	Default     : Left 0, Top 0, Width 320, Height 240
	Pixel Aspect: 1/1
Video input : 0 (Camera 1: ok)
Streaming Parameters Video Capture:
	Capabilities     : timeperframe
	Frames per second: 15.000 (15/1)
	Read buffers     : 0
#

My camera works fine... test yours out using luvcview(). It seems to me that image capture: cat /dev/video0>img.jpg; would be impossible until the device was put up.
You can peruse the source and find out how luvcview() interfaces with the camera.
http://mxhaard.free.fr/spca50x/Investigation/uvc/

Code:

# luvcview -f yuv
luvcview version 0.2.1 
Video driver: x11
A window manager is available
video /dev/video0 

Stop asked
 Clean Up done Quit 
#