[PATCH 6.18 481/752] media: uvcvideo: Fix support for V4L2_CTRL_FLAG_HAS_WHICH_MIN_MAX

Sasha Levin
2026-02-28T17:54:56Z

From: Ricardo Ribalda <ribalda@chromium.org>

[ Upstream commit 4238bd6dc6ba36f44d89a60338223d5a4f708cbf ]

The VIDIOC_G_EXT_CTRLS with which V4L2_CTRL_WHICH_(MIN|MAX)_VAL can only
work for controls that have previously announced support for it.

This patch fixes the following v4l2-compliance error:

info: checking extended control 'User Controls' (0x00980001)
fail: v4l2-test-controls.cpp(980): ret != EINVAL (got 13)
test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL

Fixes: 39d2c891c96e ("media: uvcvideo: support V4L2_CTRL_WHICH_MIN/MAX_VAL")
Cc: stable@vger.kernel.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/usb/uvc/uvc_ctrl.c | 14 ++++++++++++--
drivers/media/usb/uvc/uvc_v4l2.c | 10 ++++++----
drivers/media/usb/uvc/uvcvideo.h | 2 +-
3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 2905505c240c0..2738ef74c7373 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1432,7 +1432,7 @@ static bool uvc_ctrl_is_readable(u32 which, struct uvc_control *ctrl,
* auto_exposure=1, exposure_time_absolute=251.
*/
int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
- const struct v4l2_ext_controls *ctrls,
+ const struct v4l2_ext_controls *ctrls, u32 which,
unsigned long ioctl)
{
struct uvc_control_mapping *master_map = NULL;
@@ -1442,14 +1442,24 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
s32 val;
int ret;
int i;
+ /*
+ * There is no need to check the ioctl, all the ioctls except
+ * VIDIOC_G_EXT_CTRLS use which=V4L2_CTRL_WHICH_CUR_VAL.
+ */
+ bool is_which_min_max = which == V4L2_CTRL_WHICH_MIN_VAL ||
+ which == V4L2_CTRL_WHICH_MAX_VAL;

if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0)
- return -EACCES;
+ return is_which_min_max ? -EINVAL : -EACCES;

ctrl = uvc_find_control(chain, v4l2_id, &mapping);
if (!ctrl)
return -EINVAL;

+ if ((!(ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN) ||
+ !(ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX)) && is_which_min_max)
+ return -EINVAL;
+
if (ioctl == VIDIOC_G_EXT_CTRLS)
return uvc_ctrl_is_readable(ctrls->which, ctrl, mapping);

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 9e4a251eca880..30c160daed8cb 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -765,14 +765,15 @@ static int uvc_ioctl_query_ext_ctrl(struct file *file, void *priv,

static int uvc_ctrl_check_access(struct uvc_video_chain *chain,
struct v4l2_ext_controls *ctrls,
- unsigned long ioctl)
+ u32 which, unsigned long ioctl)
{
struct v4l2_ext_control *ctrl = ctrls->controls;
unsigned int i;
int ret = 0;

for (i = 0; i < ctrls->count; ++ctrl, ++i) {
- ret = uvc_ctrl_is_accessible(chain, ctrl->id, ctrls, ioctl);
+ ret = uvc_ctrl_is_accessible(chain, ctrl->id, ctrls, which,
+ ioctl);
if (ret)
break;
}
@@ -806,7 +807,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *priv,
which = V4L2_CTRL_WHICH_CUR_VAL;
}

- ret = uvc_ctrl_check_access(chain, ctrls, VIDIOC_G_EXT_CTRLS);
+ ret = uvc_ctrl_check_access(chain, ctrls, which, VIDIOC_G_EXT_CTRLS);
if (ret < 0)
return ret;

@@ -840,7 +841,8 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
if (!ctrls->count)
return 0;

- ret = uvc_ctrl_check_access(chain, ctrls, ioctl);
+ ret = uvc_ctrl_check_access(chain, ctrls, V4L2_CTRL_WHICH_CUR_VAL,
+ ioctl);
if (ret < 0)
return ret;

diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 3f2e832025e71..8480d65ecb85e 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -787,7 +787,7 @@ int uvc_ctrl_get(struct uvc_video_chain *chain, u32 which,
struct v4l2_ext_control *xctrl);
int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);
int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
- const struct v4l2_ext_controls *ctrls,
+ const struct v4l2_ext_controls *ctrls, u32 which,
unsigned long ioctl);

int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
--
2.51.0