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v4l2: iterate controls with V4L2_CTRL_FLAG_NEXT_CTRL if possible

Browse source 
In v2.6.18 control classes where added to the v4l2 API.
Iterating over CIDs starting with V4L2_CID_BASE will only find controls for
the first control class.
By iterating with V4L2_CTRL_FLAG_NEXT_CTRL all controls are found.

This is necessary to make controls from other control classes available in
the extra-controls property.

If V4L2_CTRL_FLAG_NEXT_CTRL is not defined at compile time or not supported
at runtime then the old mechanism for iterating is used.

https://bugzilla.gnome.org/show_bug.cgi?id=701540
This commit is contained in:
Michael Olbrich 2013-06-03 09:17:43 +02:00 committed by Sebastian Dröge
parent 0d27829a6b
commit 0769a78dd1
1 changed files with 33 additions and 4 deletions
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37
sys/v4l2/v4l2_calls.c
View file

@ -109,7 +109,8 @@ cap_failed:
static gboolean
gst_v4l2_fill_lists (GstV4l2Object * v4l2object)
{
gint n;
gint n, next;
struct v4l2_queryctrl control = { 0, };
GstElement *e;
@ -237,11 +238,21 @@ gst_v4l2_fill_lists (GstV4l2Object * v4l2object)
GST_DEBUG_OBJECT (e, " controls+menus");
/* and lastly, controls+menus (if appropriate) */
for (n = V4L2_CID_BASE;; n++) {
struct v4l2_queryctrl control = { 0, };
#ifdef V4L2_CTRL_FLAG_NEXT_CTRL
next = V4L2_CTRL_FLAG_NEXT_CTRL;
n = 0;
#else
next = 0;
n = V4L2_CID_BASE;
#endif
control.id = next;
while (TRUE) {
GstV4l2ColorBalanceChannel *v4l2channel;
GstColorBalanceChannel *channel;
if (!next)
n++;
/* when we reached the last official CID, continue with private CIDs */
if (n == V4L2_CID_LASTP1) {
GST_DEBUG_OBJECT (e, "checking private CIDs");
@ -249,8 +260,19 @@ gst_v4l2_fill_lists (GstV4l2Object * v4l2object)
}
GST_DEBUG_OBJECT (e, "checking control %08x", n);
control.id = n;
control.id = n | next;
if (v4l2_ioctl (v4l2object->video_fd, VIDIOC_QUERYCTRL, &control) < 0) {
if (next) {
if (n > 0) {
GST_DEBUG_OBJECT (e, "controls finished");
break;
} else {
GST_DEBUG_OBJECT (e, "V4L2_CTRL_FLAG_NEXT_CTRL not supported.");
next = 0;
n = V4L2_CID_BASE;
continue;
}
}
if (errno == EINVAL || errno == ENOTTY || errno == EIO || errno == ENOENT) {
if (n < V4L2_CID_PRIVATE_BASE) {
GST_DEBUG_OBJECT (e, "skipping control %08x", n);
@ -266,10 +288,17 @@ gst_v4l2_fill_lists (GstV4l2Object * v4l2object)
continue;
}
}
n = control.id;
if (control.flags & V4L2_CTRL_FLAG_DISABLED) {
GST_DEBUG_OBJECT (e, "skipping disabled control");
continue;
}
#ifdef V4L2_CTRL_TYPE_CTRL_CLASS
if (control.type == V4L2_CTRL_TYPE_CTRL_CLASS) {
GST_DEBUG_OBJECT (e, "starting control class '%s'", control.name);
continue;
}
#endif
switch (control.type) {
case V4L2_CTRL_TYPE_INTEGER:
case V4L2_CTRL_TYPE_BOOLEAN: