webcamd/cuse4bsd && Skype

[Matthias Apitz]

El día Thursday, January 05, 2012 a las 07:00:01PM +0100, Hans Petter Selasky escribió:

> > > > I checked the source tree for 'CONFIG_VIDEO_V4L1_COMPAT' but it is only
> > > > mentioned as #undef CONFIG_VIDEO_V4L1_COMPAT in build/config.h, no
> > > > further places; so I don't know where to look if some additional lib is
> > > > compiled and linked static to webcamd (ldd does not show any additional
> > > > shared lib); I'm a bit clueless; please help
> > 
> > Hi,
> > 
> > OK concerning HAL, but the main question is why the V4L IOCTL are not
> > translated into V4L2? where should I look? thanks
> 
> They are, but probably the structure size is wrong.

Hi,

Sorry for disagreeing; webcamd goes with a V4L cmd (0x40047601) into the
routines of media_tree/drivers/media/video/v4l2-ioctl.c and tries to
find a match there; the source reads:

static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
                            void * __user *user_ptr, void ***kernel_ptr)
{
        int ret = 0;

        switch (cmd) {
        case VIDIOC_QUERYBUF:
        case VIDIOC_QBUF:
        case VIDIOC_DQBUF: {
                struct v4l2_buffer *buf = parg;
...

and I have it in GDB as:

(gdb) s
check_array_args (cmd=1074034177, parg=0xbf4f9d94,
array_size=0xbf4f9d80, 
    user_ptr=0xbf4f9d7c, kernel_ptr=0xbf4f9d78)
    at media_tree/drivers/media/video/v4l2-ioctl.c:2202
2202            int ret = 0;
(gdb) n
2204            switch (cmd) {
(gdb) 
2239            return ret;
(gdb) p ret
$8 = 0
(gdb) p /x cmd
$9 = 0x40047601

i.e. it can not find any match with cmd=0x40047601 in the defines of

/usr/local/include/linux/videodev2.h

/*
 *      I O C T L   C O D E S   F O R   V I D E O   D E V I C E S
 *
 */
#define VIDIOC_QUERYCAP          _IOR('V',  0, struct v4l2_capability)
#define VIDIOC_RESERVED           _IO('V',  1)
#define VIDIOC_ENUM_FMT         _IOWR('V',  2, struct v4l2_fmtdesc)
#define VIDIOC_G_FMT            _IOWR('V',  4, struct v4l2_format)
#define VIDIOC_S_FMT            _IOWR('V',  5, struct v4l2_format)
#define VIDIOC_REQBUFS          _IOWR('V',  8, struct v4l2_requestbuffers)
...

they are all there with capital 'V' while we have 'v' (0x76) im the cmd;
this can not work; somewhere the conversion from V4L to V4L2 is missed;
where this should be done, please point me to the source file to check
and set a breakpoint there; thanks

	matthias

-- 
Matthias Apitz
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