[sane-devel] Can't access bttv card
Tue, 20 Aug 2002 11:27:30 +0200
This is my first post to the ML. I'd like to be more contributive, but
right now I'm quite busy with other kinds of work.
> > I know that the card works because I can run xawtv and get a picture.
> Does scanimage -L show your v4l device?
Does V4L devices detection works at all?
I mean, looking at the code inside V4L, in sane_init there's a call to
attach that reads:
605: attach(dev_name, 0);
But in the attach function, declared you find:
178: static SANE_Status
179: attach(const char *devname, V4L_Device **devp)
181: V4L_Device *q;
184: return SANE_STATUS_INVAL;
186: errno = 0,
Providing a pointer from the sane_init function does allow to list V4L
devices again, but I've still seen too little of the V4L code to
understand why the attach function isn't called with a valid devp from
The CVS commit code (I think.. or maybe the Changelog) say something about
avoiding memory leaks, and that's what could happen here if the list
created in attach isn't freed, as it should happen when you only call
BTW, since in sane_open the attach function is called with full
parameters, the device should work. You only have to give the full device
name to the scanning program, that is v4l:/dev/video0 or v4l:/dev/bttv
BTW, I'm here to try to be able to use the V4L interface with a USB webcam
(OV511), and that still continue do be broken, maybe due to some changes
in the way the kernel interface with the device changed recently: I think
this may be the case because the cam works with xawtv, but doesn't with
KWinTV. And since xawtv is from Gert Knorr (aka V4L mantainer...).
Latest news: I just tried both bttv and ov511 on another computer I have
here, with SuSE's sane 1.0.7: I get a segfault from my BTTV card, and a
black screen from by OV511 webcam, and a segfault after a while. I'll try
with selfcompiled 1.0.8, but maybe sane V4L suport for V4L in kernel
2.4.? is "a little" broken...