[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: mknod /dev/video0



Citerat från  Orjan Friberg <orjan.friberg@xxxxxxx.com>:

> Markus Nilsson wrote:
> > 
> > There is noone! and i can't make one "manually" as bttv doc says
> like
> > 
> >     mknod /dev/video0 c 81 0
> > 
> > because I have no permission to write to "/dev" on dev-board.
> 
> Actually, it's because the /dev directory (and most others) are
> read-only.
> 
> > What do I got to do to make this character device file?
> 
> The various device files are created by
> packages/devices/axis-2.4/Makefile, so you need to add something like:
> 
>         @$(MKNOD) -m 0666           $(DEV)/video0    c 81    0
> 
> (You can create device files on the fly by placing them in /etc
> somewhere, but then you need to be able to specify the path to the
> device file to whatever program you're running.)
> 
> -- 
> Orjan Friberg
> Axis Communications AB
> 

Ok, I got my /dev/video0 and also /proc/video.
But I can't open the video0 file after I connect my USB webcam.
The webcam appears in /proc USB fs but not in /proc video fs.
I'v got to mount /proc usbfs manually.
Do I have to do something similar with /proc video?

Another observation:
When I connect the USB webcam to my PC (same kernel) the character device looks like

   crw-------    1 markus   sys       81,   0 jan  1  1970 video0

and to dev board (connected or not)

   crw-rw-rw-    1 root     root       81,   0 Jan  1  1970 video0

I wonder about the group setting, sys and root? Important?

/Markus