This patch adds the uvc_v4l2_try_format api call to validate
the setting of v4l2_format. It will fallback to the nearest
allowed framesize.
Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
---
v13 -> v1:
- moved to this smaller patch series
v1 -> v2:
- declaring all helper functions as static
drivers/usb/gadget/function/uvc_v4l2.c | 110 +++++++++++++++++++++++++
1 file changed, 110 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index 417655e4a83dd7..c4ed48d6b8a407 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -48,6 +48,31 @@ static struct uvc_format_desc *to_uvc_format(struct uvcg_format *uformat)
return format;
}
+static int uvc_v4l2_get_bytesperline(struct uvcg_format *uformat,
+ struct uvcg_frame *uframe)
+{
+ struct uvcg_uncompressed *u;
+
+ if (uformat->type == UVCG_UNCOMPRESSED) {
+ u = to_uvcg_uncompressed(&uformat->group.cg_item);
+ if (!u)
+ return 0;
+
+ return u->desc.bBitsPerPixel * uframe->frame.w_width / 8;
+ }
+
+ return 0;
+}
+
+static int uvc_get_frame_size(struct uvcg_format *uformat,
+ struct uvcg_frame *uframe)
+{
+ unsigned int bpl = uvc_v4l2_get_bytesperline(uformat, uframe);
+
+ return bpl ? bpl * uframe->frame.w_height :
+ uframe->frame.dw_max_video_frame_buffer_size;
+}
+
static struct uvcg_format *find_format_by_index(struct uvc_device *uvc, int index)
{
struct uvcg_format_ptr *format;
@@ -105,6 +130,50 @@ static struct uvcg_format *find_format_by_pix(struct uvc_device *uvc,
return uformat;
}
+static struct uvcg_frame *find_closest_frame_by_size(struct uvc_device *uvc,
+ struct uvcg_format *uformat,
+ u16 rw, u16 rh)
+{
+ struct uvc_video *video = &uvc->video;
+ struct uvcg_format_ptr *format;
+ struct uvcg_frame_ptr *frame;
+ struct uvcg_frame *uframe = NULL;
+ unsigned int d, maxd;
+
+ /* Find the closest image size. The distance between image sizes is
+ * the size in pixels of the non-overlapping regions between the
+ * requested size and the frame-specified size.
+ */
+ maxd = (unsigned int)-1;
+
+ list_for_each_entry(format, &uvc->header->formats, entry) {
+ if (format->fmt->type != uformat->type)
+ continue;
+
+ list_for_each_entry(frame, &format->fmt->frames, entry) {
+ u16 w, h;
+
+ w = frame->frm->frame.w_width;
+ h = frame->frm->frame.w_height;
+
+ d = min(w, rw) * min(h, rh);
+ d = w*h + rw*rh - 2*d;
+ if (d < maxd) {
+ maxd = d;
+ uframe = frame->frm;
+ }
+
+ if (maxd == 0)
+ break;
+ }
+ }
+
+ if (!uframe)
+ uvcg_dbg(&video->uvc->func, "Unsupported size %ux%u\n", rw, rh);
+
+ return uframe;
+}
+
/* --------------------------------------------------------------------------
* Requests handling
*/
@@ -214,6 +283,46 @@ uvc_v4l2_set_format(struct file *file, void *fh, struct v4l2_format *fmt)
return 0;
}
+static int
+uvc_v4l2_try_format(struct file *file, void *fh, struct v4l2_format *fmt)
+{
+ struct video_device *vdev = video_devdata(file);
+ struct uvc_device *uvc = video_get_drvdata(vdev);
+ struct uvc_video *video = &uvc->video;
+ struct uvcg_format *uformat;
+ struct uvcg_frame *uframe;
+ u8 *fcc;
+
+ if (fmt->type != video->queue.queue.type)
+ return -EINVAL;
+
+ fcc = (u8 *)&fmt->fmt.pix.pixelformat;
+ uvcg_dbg(&uvc->func, "Trying format 0x%08x (%c%c%c%c): %ux%u\n",
+ fmt->fmt.pix.pixelformat,
+ fcc[0], fcc[1], fcc[2], fcc[3],
+ fmt->fmt.pix.width, fmt->fmt.pix.height);
+
+ uformat = find_format_by_pix(uvc, fmt->fmt.pix.pixelformat);
+ if (!uformat)
+ return -EINVAL;
+
+ uframe = find_closest_frame_by_size(uvc, uformat,
+ fmt->fmt.pix.width, fmt->fmt.pix.height);
+ if (!uframe)
+ return -EINVAL;
+
+ fmt->fmt.pix.width = uframe->frame.w_width;
+ fmt->fmt.pix.height = uframe->frame.w_height;
+ fmt->fmt.pix.field = V4L2_FIELD_NONE;
+ fmt->fmt.pix.bytesperline = uvc_v4l2_get_bytesperline(uformat, uframe);
+ fmt->fmt.pix.sizeimage = uvc_get_frame_size(uformat, uframe);
+ fmt->fmt.pix.pixelformat = to_uvc_format(uformat)->fcc;
+ fmt->fmt.pix.colorspace = V4L2_COLORSPACE_SRGB;
+ fmt->fmt.pix.priv = 0;
+
+ return 0;
+}
+
static int
uvc_v4l2_enum_frameintervals(struct file *file, void *fh,
struct v4l2_frmivalenum *fival)
@@ -471,6 +580,7 @@ uvc_v4l2_ioctl_default(struct file *file, void *fh, bool valid_prio,
const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = {
.vidioc_querycap = uvc_v4l2_querycap,
+ .vidioc_try_fmt_vid_out = uvc_v4l2_try_format,
.vidioc_g_fmt_vid_out = uvc_v4l2_get_format,
.vidioc_s_fmt_vid_out = uvc_v4l2_set_format,
.vidioc_enum_frameintervals = uvc_v4l2_enum_frameintervals,
--
2.30.2
