Re: [libdc1394-devel] tutorials revisited; DMA problems

[Dan D. <da...@de...>]

On Wed, 2003-06-18 at 04:49, Kero van Gelder wrote:
> > You need one video1394 device per camera you plan to use simultaneously.

No, this is incorrect. There is one video1394 device file per OHCI host
adapater.

> > In odrer to have a 'devfs'-like tree (for further compatibility) it is a
> > good practice to have video1394 devices created as /dev/video1394/0,
> > /dev/video1394/1,...

Correct.

> > You can create the devices like this (you must be root of course):
> > 
> > rm -rf /dev/video1394
> > mkdir /dev/video1394
> > mknod -m 666 /dev/video1394/0 c 171 16
> > mknod -m 666 /dev/video1394/1 c 171 17
> > mknod -m 666 /dev/video1394/3 c 171 18
> > mknod -m 666 /dev/video1394/4 c 171 19
> > 
> > I think this is explained on www.linux1394.org

Correct.

> OK, so I had a proper device, at least. Subtle difference, old:
>   crw-------    1 gelderk  root     171,  16 Jan 28  2000  /dev/video1394
> vs new
>   crw-r--r--    1 root     root     171,  16 Jan 28  2000  /dev/video1394/0
> 
> Apparently it's enough. I get max framerate+resolution of the camera
> at zero processor load, so it must be DMA :)

great!