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[media] em28xx: properly handle subdev controls

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Subdev controls return codes are evil, as they return -EINVAL to mean
both unsupported and invalid arguments. Due to that, we need to use a
trick to identify what controls are supported by a subdev.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2011-02-22 01:00:58 -03:00
parent 78e51566f0
commit fb8decfabd
1 changed files with 28 additions and 3 deletions
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31
drivers/media/video/em28xx/em28xx-video.c
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@ -1387,6 +1387,27 @@ static int vidioc_queryctrl(struct file *file, void *priv,
return -EINVAL;
}
/*
* FIXME: This is an indirect way to check if a control exists at a
* subdev. Instead of that hack, maybe the better would be to change all
* subdevs to return -ENOIOCTLCMD, if an ioctl is not supported.
*/
static int check_subdev_ctrl(struct em28xx *dev, int id)
{
struct v4l2_queryctrl qc;
memset(&qc, 0, sizeof(qc));
qc.id = id;
/* enumerate V4L2 device controls */
v4l2_device_call_all(&dev->v4l2_dev, 0, core, queryctrl, &qc);
if (qc.type)
return 0;
else
return -EINVAL;
}
static int vidioc_g_ctrl(struct file *file, void *priv,
struct v4l2_control *ctrl)
{
@ -1399,7 +1420,6 @@ static int vidioc_g_ctrl(struct file *file, void *priv,
return rc;
rc = 0;
/* Set an AC97 control */
if (dev->audio_mode.ac97 != EM28XX_NO_AC97)
rc = ac97_get_ctrl(dev, ctrl);
@ -1408,6 +1428,9 @@ static int vidioc_g_ctrl(struct file *file, void *priv,
/* It were not an AC97 control. Sends it to the v4l2 dev interface */
if (rc == 1) {
if (check_subdev_ctrl(dev, ctrl->id))
return -EINVAL;
v4l2_device_call_all(&dev->v4l2_dev, 0, core, g_ctrl, ctrl);
rc = 0;
}
@ -1434,8 +1457,10 @@ static int vidioc_s_ctrl(struct file *file, void *priv,
/* It isn't an AC97 control. Sends it to the v4l2 dev interface */
if (rc == 1) {
rc = v4l2_device_call_until_err(&dev->v4l2_dev, 0, core, s_ctrl, ctrl);
rc = check_subdev_ctrl(dev, ctrl->id);
if (!rc)
v4l2_device_call_all(&dev->v4l2_dev, 0,
core, s_ctrl, ctrl);
/*
* In the case of non-AC97 volume controls, we still need
* to do some setups at em28xx, in order to mute/unmute