[question] v4l read() operation

[Ezequiel García]

Hi Dave,

2012/2/25 Dave Hylands <dhylands at gmail.com>:
>
> I'm not all that familiar with v4l, but based on what you've posted,
> you need to populate the read routine in your v4l2_fops structure to
> support read.
>

My bad! You are totally right: I forgot about my webcam.
When I did:

$ cat /dev/video0

I was actually getting data from my webcam (which supports read),
and not from the easycap device, which is /dev/video1.

So, everything makes sense now:

$ cat /dev/video1

...
open("/dev/video1", O_RDONLY|O_LARGEFILE) = 3
...
read(3, 0x8835000, 32768)               = -1 EINVAL (Invalid argument)

This is clearly shown by the piece of code mentioned before.

Thanks and sorry for the noise,
Ezequiel.