If an error is found when validating the list of controls passed with
VIDIOC_G_EXT_CTRLS, then error_idx shall be set to ctrls->count to
indicate to userspace that no actual hardware was touched.
It would have been much nicer of course if error_idx could point to the
control index that failed the validation, but sadly that's not how the
API was designed.
Fixes v4l2-compliance:
Control ioctls (Input 0):
fail: v4l2-test-controls.cpp(645): invalid error index write only control
test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
drivers/media/usb/uvc/uvc_v4l2.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 157310c0ca87..36eb48622d48 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -1073,7 +1073,8 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,
ret = uvc_ctrl_get(chain, ctrl);
if (ret < 0) {
uvc_ctrl_rollback(handle);
- ctrls->error_idx = i;
+ ctrls->error_idx = (ret == -EACCES) ?
+ ctrls->count : i;
return ret;
}
}
--
2.31.0.rc2.261.g7f71774620-goog
