[PATCH v9 19/22] uvcvideo: uvc_ctrl_is_accessible: check for INACTIVE

[Ricardo Ribalda <ribalda@xxxxxxxxxxxx>]

From: Hans Verkuil <hverkuil@xxxxxxxxx>

Check for inactive controls in uvc_ctrl_is_accessible().
Use the new value for the master_id controls if present,
otherwise use the existing value to determine if it is OK
to set the control. Doing this here avoids attempting to
set an inactive control, which will return an error from the
USB device.

Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 28 +++++++++++++++++++++++++++-
 drivers/media/usb/uvc/uvc_v4l2.c |  4 ++--
 drivers/media/usb/uvc/uvcvideo.h |  3 ++-
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index d9d4add1e813..6e7b904bc33d 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1047,10 +1047,18 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
 }
 
 int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
-			   bool read)
+			   const struct v4l2_ext_controls *ctrls,
+			   unsigned long ioctl)
 {
+	struct uvc_control_mapping *master_map = NULL;
+	struct uvc_control *master_ctrl = NULL;
 	struct uvc_control_mapping *mapping;
 	struct uvc_control *ctrl;
+	bool read = ioctl == VIDIOC_G_EXT_CTRLS;
+	bool try = ioctl == VIDIOC_TRY_EXT_CTRLS;
+	s32 val;
+	int ret;
+	int i;
 
 	if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0)
 		return -EACCES;
@@ -1065,6 +1073,24 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
 	if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read)
 		return -EACCES;
 
+	if (read || try || !mapping->master_id)
+		return 0;
+
+	for (i = ctrls->count - 1; i >= 0; i--)
+		if (ctrls->controls[i].id == mapping->master_id)
+			return ctrls->controls[i].value ==
+					mapping->master_manual ? 0 : -EACCES;
+
+	__uvc_find_control(ctrl->entity, mapping->master_id, &master_map,
+			   &master_ctrl, 0);
+
+	if (!master_ctrl || !(master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR))
+		return 0;
+
+	ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
+	if (ret >= 0 && val != mapping->master_manual)
+		return -EACCES;
+
 	return 0;
 }
 
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 8d8b12a4db34..0f4d893eff46 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -1000,8 +1000,8 @@ static int uvc_ctrl_check_access(struct uvc_video_chain *chain,
 	int ret = 0;
 
 	for (i = 0; i < ctrls->count; ++ctrl, ++i) {
-		ret = uvc_ctrl_is_accessible(chain, ctrl->id,
-					    ioctl == VIDIOC_G_EXT_CTRLS);
+		ret = uvc_ctrl_is_accessible(chain, ctrl->id, ctrls,
+					    ioctl);
 		if (ret)
 			break;
 	}
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index 0313b30f0cea..20bc681315fb 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -901,7 +901,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle)
 int uvc_ctrl_get(struct uvc_video_chain *chain, 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,
-			   bool read);
+			   const struct v4l2_ext_controls *ctrls,
+			   unsigned long ioctl);
 
 int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
 		      struct uvc_xu_control_query *xqry);
-- 
2.31.0.291.g576ba9dcdaf-goog