Missing /dev/video[N] devices...?

Missing /dev/video[N] devices...?

[Nick Pelling]

Hi everyone,

I'm trying to bring up the 2.6.37 kernel from scratch on a new 
Samsung S5PC100-based board, but have hit a media problem. Though my 
various v4l2 devices are all registering OK during the boot process 
and end up visible in /sys/class/video4linux , they never manage to 
become visible in /dev , i.e.

	# ls /dev/video*
	ls: /dev/video*: No such file or directory

	# ls /sys/class/video4linux/
	video0   video1   video14  video2   video21  video22

	# ls /sys/class/video4linux/video0/
	dev        index      name       subsystem  uevent

	# cat /sys/class/video4linux/video0/name
	s5p-fimc.0:m2m

	# cat /sys/class/video4linux/video0/uevent
	MAJOR=81
	MINOR=0
	DEVNAME=video0

I've tried enabling everything that seems relevant in the kernel's 
menuconfig options, but it seems as though I've omitted some crucial 
piece of the v4l2 infrastructure. Any suggestions for what's missing?

Thanks!, ....Nick Pelling....

Missing /dev/video[N] devices...?

[Nick Pelling]

Hi everyone,

Problem solved - the boot sequence didn't have a makedev, so the 
/dev/video[N] nodes weren't getting automatically created. A few 
"mknod c X  Y" commands later, all the /dev/video[N] items are in place. :-)

Cheers, ....Nick Pelling....

Re: Missing /dev/video[N] devices...?

[Andy Walls]

Nick Pelling <nickpelling@nanodome.com> wrote:

>Hi everyone,
>
>I'm trying to bring up the 2.6.37 kernel from scratch on a new 
>Samsung S5PC100-based board, but have hit a media problem. Though my 
>various v4l2 devices are all registering OK during the boot process 
>and end up visible in /sys/class/video4linux , they never manage to 
>become visible in /dev , i.e.
>
>	# ls /dev/video*
>	ls: /dev/video*: No such file or directory
>
>	# ls /sys/class/video4linux/
>	video0   video1   video14  video2   video21  video22
>
>	# ls /sys/class/video4linux/video0/
>	dev        index      name       subsystem  uevent
>
>	# cat /sys/class/video4linux/video0/name
>	s5p-fimc.0:m2m
>
>	# cat /sys/class/video4linux/video0/uevent
>	MAJOR=81
>	MINOR=0
>	DEVNAME=video0
>
>I've tried enabling everything that seems relevant in the kernel's 
>menuconfig options, but it seems as though I've omitted some crucial 
>piece of the v4l2 infrastructure. Any suggestions for what's missing?
>
>Thanks!, ....Nick Pelling....
>
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I thought udev normally makes those nodes.

On embedded systems there is a different, smaller user space app responding to hotplug events including firmware load requests.

-Andy