Hi Huzaifa,
First of all many thanks for working on this!
Comments inline.
On 05/18/2010 01:12 PM, Huzaifa Sidhpurwala wrote:
Hi All,
I have been working with Hans for moving the v4l1 ioctls from the kernel
to libv4l1.
It would be best to work on one ioctl at a time.
The enclosed patch attempts to implement VIDIOCGCAP in the libv4l1.
Note: Hans is working with Bill, asking for permission to re-use the
v4l1-compat.c code under the LGPL
diff --git a/lib/libv4l1/libv4l1.c b/lib/libv4l1/libv4l1.c
index eae3b43..8571651 100644
--- a/lib/libv4l1/libv4l1.c
+++ b/lib/libv4l1/libv4l1.c
@@ -61,6 +61,10 @@
#define V4L1_PIX_FMT_TOUCHED 0x04
#define V4L1_PIX_SIZE_TOUCHED 0x08
+#ifndef min
+ #define min( a, b ) ( ((a)< (b)) ? (a) : (b) )
+#endif
+
static pthread_mutex_t v4l1_open_mutex = PTHREAD_MUTEX_INITIALIZER;
static struct v4l1_dev_info devices[V4L1_MAX_DEVICES] = {
{ .fd = -1 },
@@ -130,6 +134,45 @@ static unsigned int pixelformat_to_palette(unsigned
int pixelformat)
return 0;
}
+static int count_inputs(int fd)
+{
+ struct v4l2_input input2;
+ int i;
+ for (i = 0;; i++) {
+ memset(&input2, 0, sizeof(input2));
+ input2.index = i;
+ if (0 != SYS_IOCTL(fd, VIDIOC_ENUMINPUT,&input2))
+ break;
+ }
+ return i;
+}
+
+static int check_size(int fd,int *maxw,int *maxh)
+{
+ struct v4l2_fmtdesc desc2;
+ struct v4l2_format fmt2;
+
+ memset(&desc2, 0, sizeof(desc2));
+ memset(&fmt2, 0, sizeof(fmt2));
+
+ desc2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+ if (0 != SYS_IOCTL(fd, VIDIOC_ENUM_FMT,&desc2))
+ goto done;
+
+ fmt2.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+ fmt2.fmt.pix.width = 10000;
+ fmt2.fmt.pix.height = 10000;
+ fmt2.fmt.pix.pixelformat = desc2.pixelformat;
+ if (0 != SYS_IOCTL(fd, VIDIOC_TRY_FMT,&fmt2))
+ goto done;
+
+ *maxw = fmt2.fmt.pix.width;
+ *maxh = fmt2.fmt.pix.height;
+
+ done:
+ return 0;
+}
+
We don't need this function, see below.
static int v4l1_set_format(int index, unsigned int width,
unsigned int height, int v4l1_pal, int width_height_may_differ)
{
@@ -492,7 +535,54 @@ int v4l1_ioctl(int fd, unsigned long int request, ...)
case VIDIOCGCAP: {
struct video_capability *cap = arg;
- result = SYS_IOCTL(fd, request, arg);
+ long err;
+ struct v4l2_framebuffer fbuf;
+ struct v4l2_capability *cap2;
The kernel mallocs struct v4l2_capability because the kernel
stack is severely limited, no need to do that in userspace, just
put the entire struct on the stack.
+
+ cap2 = malloc (sizeof(*cap2));
+ if (!cap2) {
+ return -ENOMEM;
+ }
+
+ memset(cap,0,sizeof(*cap));
+ memset(&fbuf, 0, sizeof(fbuf));
+
You can get the memset effect, by initalizing the first field of the
struct to 0, the compiler will then 0 out the rest:
struct v4l2_framebuffer fbuf = { 0, };
struct v4l2_capability cap2 = { 0, };
+ err = SYS_IOCTL(fd, VIDIOC_QUERYCAP,cap2);
+ if (err< 0)
+ goto done;
+
+ if (cap2->capabilities& V4L2_CAP_VIDEO_OVERLAY) {
+ err = SYS_IOCTL(fd, VIDIOC_G_FBUF,&fbuf);
+ if (err< 0) {
+ memset(&fbuf, 0, sizeof(fbuf));
+ }
+ err = 0;
+ }
+
+ memcpy(cap->name, cap2->card,
min(sizeof(cap->name),sizeof(cap2->card)) );
+
+ cap->name[sizeof(cap->name) -1 ] = 0;
+
+ if (cap2->capabilities& V4L2_CAP_VIDEO_CAPTURE)
+ cap->type |= VID_TYPE_CAPTURE;
+ if (cap2->capabilities& V4L2_CAP_TUNER)
+ cap->type |= VID_TYPE_TUNER;
+ if (cap2->capabilities& V4L2_CAP_VBI_CAPTURE)
+ cap->type |= VID_TYPE_TELETEXT;
+ if (cap2->capabilities& V4L2_CAP_VIDEO_OVERLAY)
+ cap->type |= VID_TYPE_OVERLAY;
+ if (fbuf.capability& V4L2_FBUF_CAP_LIST_CLIPPING)
+ cap->type |= VID_TYPE_CLIPPING;
+
+ cap->channels = count_inputs(fd);
+
+ check_size(fd,
+ &cap->maxwidth,&cap->maxheight);
+
No need to check size here, as we override that below, so this line can
be dropped.
+
+ /* result = SYS_IOCTL(fd, request, arg);*/
+
This can be dropped too.
+
/* override kernel v4l1 compat min / max size with our own more
accurate values */
And the override comment can be dropped to, as we no longer will be
suing the v4l1 compat code check_size stuff.
@@ -500,7 +590,10 @@ int v4l1_ioctl(int fd, unsigned long int request, ...)
cap->minheight = devices[index].min_height;
cap->maxwidth = devices[index].max_width;
cap->maxheight = devices[index].max_height;
- break;
+
+ done:
+ free(cap2);
+ break;
}
No need to do this either when we drop the malloc.
case VIDIOCSPICT: {
Thanks & Regards,
Hans
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