Re: VIDIOCGMBUF "Invalid argument" (hasciicam on eee, 2.6.27-8-eeepc)

[Laurent Pinchart <laurent.pinchart@xxxxxxxxx>]

Hi Dan,

On Sunday 01 February 2009, D wrote:
> Hi -
>
> I have an asus eee running eeebuntu 8.10, and I'm trying to get
> hasciicam [1] to work with the built-in UVC webcam. (All works fine
> when using "cheese" to confirm the webcam is working.) The hasciicam
> code calls the VIDIOCGMBUF ioctl and that's where it fails. Here's the
> code (from hasciicam.c):
>
>   if (ioctl (dev, VIDIOCGMBUF, &grab_map) == -1) {
>     perror("!! error in ioctl VIDIOCGMBUF: ");
>     return -1;
>   }
>
> ...where dev is pretty definitely open (we have already successfully
> called VIDIOCGCAP and suchlike), and grab_map is a struct of type
> video_mbuf as it should be. And here's the result:
>
>   !! error in ioctl VIDIOCGMBUF: Invalid argument
>
> Does this suggest that hasciicam is calling the ioctl incorrectly?
> (For example, in [2] it says "a user first sets the desired image size
> and depth properties" before calling it, although it doesn't spell out
> precisely how that is done.) Or does it mean this particular ioctl is
> not available on the given setup?
>
> I'd be grateful for any suggestions.

The UVC driver doesn't support the deprecated V4L1 API. The v4l1compat.so 
wrapper might help you, as it translates V4L1 calls to V4L2.

Best regards,

Laurent Pinchart

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