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Subject[PATCH 1/2] v4l2: modify the webcam video standard handling
From: Márton Németh <nm127@freemail.hu>

Change the handling of the case when vdev->tvnorms == 0.

From V4L2 API specification, rev. 0.24 [1]:
> Special rules apply to USB cameras where the notion of video
> standards makes little sense. More generally any capture device,
> output devices accordingly, which is
>
> * incapable of capturing fields or frames at the nominal rate
> of the video standard, or
> * where timestamps refer to the instant the field or frame was
> received by the driver, not the capture time, or
> * where sequence numbers refer to the frames received by the
> driver, not the captured frames.
>
> Here the driver shall set the std field of struct v4l2_input
> and struct v4l2_output to zero, the VIDIOC_G_STD, VIDIOC_S_STD,
> VIDIOC_QUERYSTD and VIDIOC_ENUMSTD ioctls shall return the
> EINVAL error code.

The changeset was tested together with v4l-test 0.16 [2] with
gspca_sunplus driver together with Trust 610 LCD POWERC@M ZOOM.

References:
[1] V4L2 API specification, revision 0.24
http://v4l2spec.bytesex.org/spec/x448.htm

[2] v4l-test: Test environment for Video For Linux Two API
http://v4l-test.sourceforge.net/

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
diff -upr linux-2.6.31-rc1.orig/drivers/media/video/v4l2-dev.c linux-2.6.31-rc1/drivers/media/video/v4l2-dev.c
--- linux-2.6.31-rc1.orig/drivers/media/video/v4l2-dev.c 2009-06-25 01:25:37.000000000 +0200
+++ linux-2.6.31-rc1/drivers/media/video/v4l2-dev.c 2009-07-06 07:48:13.000000000 +0200
@@ -397,6 +397,11 @@ int video_register_device_index(struct v
if (!vdev->release)
return -EINVAL;

+ /* if no video standards are supported then no need to get and set
+ them: they will never be called */
+ WARN_ON(!vdev->tvnorms && vdev->ioctl_ops->vidioc_g_std);
+ WARN_ON(!vdev->tvnorms && vdev->ioctl_ops->vidioc_s_std);
+
/* Part 1: check device type */
switch (type) {
case VFL_TYPE_GRABBER:
diff -upr linux-2.6.31-rc1.orig/drivers/media/video/v4l2-ioctl.c linux-2.6.31-rc1/drivers/media/video/v4l2-ioctl.c
--- linux-2.6.31-rc1.orig/drivers/media/video/v4l2-ioctl.c 2009-06-25 01:25:37.000000000 +0200
+++ linux-2.6.31-rc1/drivers/media/video/v4l2-ioctl.c 2009-07-06 07:41:23.000000000 +0200
@@ -1077,12 +1077,15 @@ static long __video_do_ioctl(struct file
{
v4l2_std_id *id = arg;

- ret = 0;
- /* Calls the specific handler */
- if (ops->vidioc_g_std)
- ret = ops->vidioc_g_std(file, fh, id);
- else
- *id = vfd->current_norm;
+ /* Check if any standard is supported */
+ if (vfd->tvnorms) {
+ ret = 0;
+ /* Calls the specific handler */
+ if (ops->vidioc_g_std)
+ ret = ops->vidioc_g_std(file, fh, id);
+ else
+ *id = vfd->current_norm;
+ }

if (!ret)
dbgarg(cmd, "std=0x%08Lx\n", (long long unsigned)*id);
@@ -1095,7 +1098,7 @@ static long __video_do_ioctl(struct file
dbgarg(cmd, "std=%08Lx\n", (long long unsigned)*id);

norm = (*id) & vfd->tvnorms;
- if (vfd->tvnorms && !norm) /* Check if std is supported */
+ if (!norm) /* Check if std is supported */
break;

/* Calls the specific handler */
--
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