I’d like to connect an USB webcam to my olimex linux board but when I plug it I can’t find in the /dev directory any video device ( something like /dev/video0 and so on).
It’s very strange because the kernel recognizes it when I plug the webcam.
Does anybody know which name the webcam has under the /dev directory?
Thank you very much.
There are many types of USB webcams and many of those use some kind of proprietary transfer protocol and proprietary image compression. Only relatively recently are USB webcams starting to use a common protocol (it’s called UVC, USB video class if I remember correctly).
At some point the Linux developers decided that it was no longer allowed to do image decompression within the webcam driver, so some kind of hybrid kernel/userspace solution is required. Last time I was involved in it, USB webcam support for Linux was very messy.
You need to know the exact type of webcam (googling with the USB VID/PID may help) and you may have to compile your own driver. Useful pages:
http://mxhaard.free.fr/index.html (open-source)
http://www.linux-projects.org (closed source)
I own a CREATIVE one , whwn I plug it I get this message:
sam9-l9260:~# usb 1-1: USB disconnect, address 5
usb 1-1: new full speed USB device using at91_ohci and address 6
usb 1-1: configuration #1 chosen from 1 choice
if I give “lsusb” I get:
lsusb
Bus 001 Device 006: ID 041e:4003 Creative Technology, Ltd VideoBlaster WebCam Go Plus [W9967CF]
Bus 001 Device 001: ID 0000:0000
sam9-l9260:~#
sam9-l9260:~#
and with “dmesg”:
…
…
usb 1-1: new full speed USB device using at91_ohci and address 2
usb 1-1: configuration #1 chosen from 1 choice
usb 1-1: USB disconnect, address 2
usb 1-1: new full speed USB device using at91_ohci and address 3
usb 1-1: configuration #1 chosen from 1 choice
usb 1-1: USB disconnect, address 3
usb 1-1: new full speed USB device using at91_ohci and address 4
usb 1-1: device descriptor read/64, error -62
usb 1-1: configuration #1 chosen from 1 choice
eth0: link up (100/Full)
usb 1-1: USB disconnect, address 4
usb 1-1: new full speed USB device using at91_ohci and address 5
usb 1-1: configuration #1 chosen from 1 choice
usb 1-1: USB disconnect, address 5
usb 1-1: new full speed USB device using at91_ohci and address 6
usb 1-1: configuration #1 chosen from 1 choice
sam9-l9260:~#
sam9-l9260:~#
in the dev directory I have this situation:
sam9-l9260:~# ls /dev
1-1\0x09 loop6\0x09 ptyp5 ram2 tty12 tty3 tty47 tty7\0x09ttypd
MAKEDEV loop7\0x09 ptyp6 ram3 tty13 tty30 tty48 tty8\0x09ttype
bus\0x09 mem\0x09 ptyp7 ram4 tty14 tty31 tty49 tty9\0x09ttypf
console mtd0\0x09 ptyp8 ram5 tty15 tty32 tty5\0x09 ttyS0\0x09urandom
core\0x09 mtd0ro ptyp9 ram6 tty16 tty33 tty50 ttyS1\0x09usb1
fd\0x09 mtd1\0x09 ptypa ram7 tty17 tty34 tty51 ttyS2\0x09usbdev1.1_ep00
full\0x09 mtd1ro ptypb ram8 tty18 tty35 tty52 ttyp0\0x09usbdev1.1_ep81
initctl mtdblock0 ptypc ram9 tty19 tty36 tty53 ttyp1\0x09usbdev1.6_ep00
input\0x09 mtdblock1 ptypd random tty2 tty37 tty54 ttyp2\0x09usbdev1.6_ep81
kmem\0x09 net\0x09 ptype shm\0x09 tty20 tty38 tty55 ttyp3\0x09vcs
kmsg\0x09 null\0x09 ptypf sndstat tty21 tty39 tty56 ttyp4\0x09vcsa
log\0x09 ppp\0x09 ram0 stderr tty22 tty4 tty57 ttyp5\0x09video0
loop\0x09 ptmx\0x09 ram1 stdin tty23 tty40 tty58 ttyp6\0x09xconsole
loop0\0x09 pts\0x09 ram10 stdout tty24 tty41 tty59 ttyp7\0x09zero
loop1\0x09 ptyp0\0x09 ram11 tty\0x09 tty25 tty42 tty6\0x09 ttyp8
loop2\0x09 ptyp1\0x09 ram12 tty0 tty26 tty43 tty60 ttyp9
loop3\0x09 ptyp2\0x09 ram13 tty1 tty27 tty44 tty61 ttypa
loop4\0x09 ptyp3\0x09 ram14 tty10 tty28 tty45 tty62 ttypb
loop5\0x09 ptyp4\0x09 ram15 tty11 tty29 tty46 tty63 ttypc
sam9-l9260:~#
sam9-l9260:~#
Please , can anybody tell me which one is my usb webcam?
I’d like to use “open” in a C program to open the webcam and get an image to store on a file.
Thank you very much.
/dev/video0
If it returns ENODEV, you still need to load the w9968cf driver.
denial:
/dev/video0If it returns ENODEV, you still need to load the w9968cf driver.
I have found only this under /dev:
ttyp5\0x09video0
is this the same thing?
caccolillo:
I have found only this under /dev:ttyp5\0x09video0
is this the same thing?
Either your /dev directory is messed up or whatever you use to access the board prints tab characters as \0x09.
There should be ttyp5 and video0 but not ttyp5\0x09video0.
denial:
caccolillo:
I have found only this under /dev:ttyp5\0x09video0
is this the same thing?
Either your /dev directory is messed up or whatever you use to access the board prints tab characters as \0x09.
There should be ttyp5 and video0 but not ttyp5\0x09video0.
It’s very strange , i’ve given again the ls command and the /video device is disappeared.
I can’t find it neither if I reboot the board.
sam9-l9260:~# ls -l /dev
total 0
crw-rw---- 1 root root 189, 1 Jan 1 02:04 1-1
lrwxrwxrwx 1 root root 13 Jan 1 02:00 MAKEDEV → /sbin/MAKEDEV
drwxr-xr-x 3 root root 60 Jan 1 02:00 bus
crw------- 1 root root 5, 1 Jan 1 02:02 console
lrwxrwxrwx 1 root root 11 Jan 1 02:00 core → /proc/kcore
lrwxrwxrwx 1 root root 13 Jan 1 02:00 fd → /proc/self/fd
crw-rw-rw- 1 root root 1, 7 Jan 1 02:00 full
prw------- 1 root root 0 Jan 1 02:00 initctl
drwxr-xr-x 2 root root 60 Jan 1 02:00 input
crw-r----- 1 root kmem 1, 2 Jan 1 02:00 kmem
crw-rw---- 1 root root 1, 11 Jan 1 02:00 kmsg
srw-rw-rw- 1 root root 0 Jan 1 02:02 log
drwxr-xr-x 2 root root 60 Jan 1 02:00 loop
brw-rw---- 1 root disk 7, 0 Jan 1 02:00 loop0
brw-rw---- 1 root disk 7, 1 Jan 1 02:00 loop1
brw-rw---- 1 root disk 7, 2 Jan 1 02:00 loop2
brw-rw---- 1 root disk 7, 3 Jan 1 02:00 loop3
brw-rw---- 1 root disk 7, 4 Jan 1 02:00 loop4
brw-rw---- 1 root disk 7, 5 Jan 1 02:00 loop5
brw-rw---- 1 root disk 7, 6 Jan 1 02:00 loop6
brw-rw---- 1 root disk 7, 7 Jan 1 02:00 loop7
crw-r----- 1 root kmem 1, 1 Jan 1 02:00 mem
crw-rw---- 1 root root 90, 0 Jan 1 02:00 mtd0
crw-rw---- 1 root root 90, 1 Jan 1 02:00 mtd0ro
crw-rw---- 1 root root 90, 2 Jan 1 02:00 mtd1
crw-rw---- 1 root root 90, 3 Jan 1 02:00 mtd1ro
brw-rw---- 1 root disk 31, 0 Jan 1 02:00 mtdblock0
brw-rw---- 1 root disk 31, 1 Jan 1 02:00 mtdblock1
drwxr-xr-x 2 root root 60 Jan 1 02:00 net
crw-rw-rw- 1 root root 1, 3 Jan 1 02:00 null
crw------- 1 root root 108, 0 Jan 1 02:00 ppp
crw-rw-rw- 1 root root 5, 2 Jan 1 02:00 ptmx
drwxr-xr-x 2 root root 0 Jan 1 02:00 pts
crw-rw-rw- 1 root tty 2, 0 Jan 1 02:00 ptyp0
crw-rw-rw- 1 root tty 2, 1 Jan 1 02:00 ptyp1
crw-rw-rw- 1 root tty 2, 2 Jan 1 02:00 ptyp2
crw-rw-rw- 1 root tty 2, 3 Jan 1 02:00 ptyp3
crw-rw-rw- 1 root tty 2, 4 Jan 1 02:00 ptyp4
crw-rw-rw- 1 root tty 2, 5 Jan 1 02:00 ptyp5
crw-rw-rw- 1 root tty 2, 6 Jan 1 02:00 ptyp6
crw-rw-rw- 1 root tty 2, 7 Jan 1 02:00 ptyp7
crw-rw-rw- 1 root tty 2, 8 Jan 1 02:00 ptyp8
crw-rw-rw- 1 root tty 2, 9 Jan 1 02:00 ptyp9
crw-rw-rw- 1 root tty 2, 10 Jan 1 02:00 ptypa
crw-rw-rw- 1 root tty 2, 11 Jan 1 02:00 ptypb
crw-rw-rw- 1 root tty 2, 12 Jan 1 02:00 ptypc
crw-rw-rw- 1 root tty 2, 13 Jan 1 02:00 ptypd
crw-rw-rw- 1 root tty 2, 14 Jan 1 02:00 ptype
crw-rw-rw- 1 root tty 2, 15 Jan 1 02:00 ptypf
brw-rw---- 1 root disk 1, 0 Jan 1 02:00 ram0
brw-rw---- 1 root disk 1, 1 Jan 1 02:00 ram1
brw-rw---- 1 root disk 1, 10 Jan 1 02:00 ram10
brw-rw---- 1 root disk 1, 11 Jan 1 02:00 ram11
brw-rw---- 1 root disk 1, 12 Jan 1 02:00 ram12
brw-rw---- 1 root disk 1, 13 Jan 1 02:00 ram13
brw-rw---- 1 root disk 1, 14 Jan 1 02:00 ram14
brw-rw---- 1 root disk 1, 15 Jan 1 02:00 ram15
brw-rw---- 1 root disk 1, 2 Jan 1 02:00 ram2
brw-rw---- 1 root disk 1, 3 Jan 1 02:00 ram3
brw-rw---- 1 root disk 1, 4 Jan 1 02:00 ram4
brw-rw---- 1 root disk 1, 5 Jan 1 02:00 ram5
brw-rw---- 1 root disk 1, 6 Jan 1 02:00 ram6
brw-rw---- 1 root disk 1, 7 Jan 1 02:00 ram7
brw-rw---- 1 root disk 1, 8 Jan 1 02:00 ram8
brw-rw---- 1 root disk 1, 9 Jan 1 02:00 ram9
crw-rw-rw- 1 root root 1, 8 Jan 1 02:00 random
drwxrwxrwt 2 root root 40 Jan 1 02:00 shm
lrwxrwxrwx 1 root root 24 Jan 1 02:00 sndstat → /proc/asound/oss/sndstat
lrwxrwxrwx 1 root root 15 Jan 1 02:00 stderr → /proc/self/fd/2
lrwxrwxrwx 1 root root 15 Jan 1 02:00 stdin → /proc/self/fd/0
lrwxrwxrwx 1 root root 15 Jan 1 02:00 stdout → /proc/self/fd/1
crw-rw-rw- 1 root root 5, 0 Jan 1 02:00 tty
crw-rw---- 1 root root 4, 0 Jan 1 02:00 tty0
crw-rw---- 1 root root 4, 1 Jan 1 02:00 tty1
crw-rw---- 1 root root 4, 10 Jan 1 02:00 tty10
crw-rw---- 1 root root 4, 11 Jan 1 02:00 tty11
crw-rw---- 1 root root 4, 12 Jan 1 02:00 tty12
crw-rw---- 1 root root 4, 13 Jan 1 02:00 tty13
crw-rw---- 1 root root 4, 14 Jan 1 02:00 tty14
crw-rw---- 1 root root 4, 15 Jan 1 02:00 tty15
crw-rw---- 1 root root 4, 16 Jan 1 02:00 tty16
crw-rw---- 1 root root 4, 17 Jan 1 02:00 tty17
crw-rw---- 1 root root 4, 18 Jan 1 02:00 tty18
crw-rw---- 1 root root 4, 19 Jan 1 02:00 tty19
crw-rw---- 1 root root 4, 2 Jan 1 02:00 tty2
crw-rw---- 1 root root 4, 20 Jan 1 02:00 tty20
crw-rw---- 1 root root 4, 21 Jan 1 02:00 tty21
crw-rw---- 1 root root 4, 22 Jan 1 02:00 tty22
crw-rw---- 1 root root 4, 23 Jan 1 02:00 tty23
crw-rw---- 1 root root 4, 24 Jan 1 02:00 tty24
crw-rw---- 1 root root 4, 25 Jan 1 02:00 tty25
crw-rw---- 1 root root 4, 26 Jan 1 02:00 tty26
crw-rw---- 1 root root 4, 27 Jan 1 02:00 tty27
crw-rw---- 1 root root 4, 28 Jan 1 02:00 tty28
crw-rw---- 1 root root 4, 29 Jan 1 02:00 tty29
crw-rw---- 1 root root 4, 3 Jan 1 02:00 tty3
crw-rw---- 1 root root 4, 30 Jan 1 02:00 tty30
crw-rw---- 1 root root 4, 31 Jan 1 02:00 tty31
crw-rw---- 1 root root 4, 32 Jan 1 02:00 tty32
crw-rw---- 1 root root 4, 33 Jan 1 02:00 tty33
crw-rw---- 1 root root 4, 34 Jan 1 02:00 tty34
crw-rw---- 1 root root 4, 35 Jan 1 02:00 tty35
crw-rw---- 1 root root 4, 36 Jan 1 02:00 tty36
crw-rw---- 1 root root 4, 37 Jan 1 02:00 tty37
crw-rw---- 1 root root 4, 38 Jan 1 02:00 tty38
crw-rw---- 1 root root 4, 39 Jan 1 02:00 tty39
crw-rw---- 1 root root 4, 4 Jan 1 02:00 tty4
crw-rw---- 1 root root 4, 40 Jan 1 02:00 tty40
crw-rw---- 1 root root 4, 41 Jan 1 02:00 tty41
crw-rw---- 1 root root 4, 42 Jan 1 02:00 tty42
crw-rw---- 1 root root 4, 43 Jan 1 02:00 tty43
crw-rw---- 1 root root 4, 44 Jan 1 02:00 tty44
crw-rw---- 1 root root 4, 45 Jan 1 02:00 tty45
crw-rw---- 1 root root 4, 46 Jan 1 02:00 tty46
crw-rw---- 1 root root 4, 47 Jan 1 02:00 tty47
crw-rw---- 1 root root 4, 48 Jan 1 02:00 tty48
crw-rw---- 1 root root 4, 49 Jan 1 02:00 tty49
crw-rw---- 1 root root 4, 5 Jan 1 02:00 tty5
crw-rw---- 1 root root 4, 50 Jan 1 02:00 tty50
crw-rw---- 1 root root 4, 51 Jan 1 02:00 tty51
crw-rw---- 1 root root 4, 52 Jan 1 02:00 tty52
crw-rw---- 1 root root 4, 53 Jan 1 02:00 tty53
crw-rw---- 1 root root 4, 54 Jan 1 02:00 tty54
crw-rw---- 1 root root 4, 55 Jan 1 02:00 tty55
crw-rw---- 1 root root 4, 56 Jan 1 02:00 tty56
crw-rw---- 1 root root 4, 57 Jan 1 02:00 tty57
crw-rw---- 1 root root 4, 58 Jan 1 02:00 tty58
crw-rw---- 1 root root 4, 59 Jan 1 02:00 tty59
crw-rw---- 1 root root 4, 6 Jan 1 02:00 tty6
crw-rw---- 1 root root 4, 60 Jan 1 02:00 tty60
crw-rw---- 1 root root 4, 61 Jan 1 02:00 tty61
crw-rw---- 1 root root 4, 62 Jan 1 02:00 tty62
crw-rw---- 1 root root 4, 63 Jan 1 02:00 tty63
crw-rw---- 1 root root 4, 7 Jan 1 02:00 tty7
crw-rw---- 1 root root 4, 8 Jan 1 02:00 tty8
crw-rw---- 1 root root 4, 9 Jan 1 02:00 tty9
crw------- 1 root tty 4, 64 Jan 1 02:08 ttyS0
crw-rw---- 1 root dialout 4, 65 Jan 1 02:00 ttyS1
crw-rw---- 1 root dialout 4, 66 Jan 1 02:00 ttyS2
crw-rw-rw- 1 root tty 3, 0 Jan 1 02:00 ttyp0
crw-rw-rw- 1 root tty 3, 1 Jan 1 02:00 ttyp1
crw-rw-rw- 1 root tty 3, 2 Jan 1 02:00 ttyp2
crw-rw-rw- 1 root tty 3, 3 Jan 1 02:00 ttyp3
crw-rw-rw- 1 root tty 3, 4 Jan 1 02:00 ttyp4
crw-rw-rw- 1 root tty 3, 5 Jan 1 02:00 ttyp5
crw-rw-rw- 1 root tty 3, 6 Jan 1 02:00 ttyp6
crw-rw-rw- 1 root tty 3, 7 Jan 1 02:00 ttyp7
crw-rw-rw- 1 root tty 3, 8 Jan 1 02:00 ttyp8
crw-rw-rw- 1 root tty 3, 9 Jan 1 02:00 ttyp9
crw-rw-rw- 1 root tty 3, 10 Jan 1 02:00 ttypa
crw-rw-rw- 1 root tty 3, 11 Jan 1 02:00 ttypb
crw-rw-rw- 1 root tty 3, 12 Jan 1 02:00 ttypc
crw-rw-rw- 1 root tty 3, 13 Jan 1 02:00 ttypd
crw-rw-rw- 1 root tty 3, 14 Jan 1 02:00 ttype
crw-rw-rw- 1 root tty 3, 15 Jan 1 02:00 ttypf
crw-rw-rw- 1 root root 1, 9 Jan 1 02:02 urandom
crw-rw---- 1 root root 189, 0 Jan 1 02:00 usb1
crw-rw---- 1 root root 253, 0 Jan 1 02:00 usbdev1.1_ep00
crw-rw---- 1 root root 253, 1 Jan 1 02:00 usbdev1.1_ep81
crw-rw---- 1 root root 253, 2 Jan 1 02:04 usbdev1.2_ep00
crw-rw---- 1 root root 253, 3 Jan 1 02:04 usbdev1.2_ep81
crw-rw---- 1 root root 7, 0 Jan 1 02:00 vcs
crw-rw---- 1 root root 7, 128 Jan 1 02:00 vcsa
prw-r----- 1 root adm 0 Jan 1 02:04 xconsole
crw-rw-rw- 1 root root 1, 5 Jan 1 02:00 zero
sam9-l9260:~#
so which of these one is the webcam and which one the SD ?
Thank you very much.
Is the webcam still connected?
Previously you had it as device 6 but now it is gone and another device 2 appeared.
and which one the SD ?
SD as in secure digital card?
Yes , the webcam has been disconnected and then reconnected.
Yes I mean a secure digital by 1GB connected to the board.