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Subject[PATCH v10 21/21] media: uvcvideo: Return -EACCES to inactive controls
Date
If a control is inactive return -EACCES to let the userspace know that
the value will not be applied automatically when the control is active
again.

Also make sure that query_v4l2_ctrl doesn't return an error.

Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
drivers/media/usb/uvc/uvc_ctrl.c | 73 +++++++++++++++++++++-----------
1 file changed, 49 insertions(+), 24 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index da44d5c0b9ad..4f80c06d3c43 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -1104,13 +1104,36 @@ static const char *uvc_map_get_name(const struct uvc_control_mapping *map)
return "Unknown Control";
}

+static bool uvc_ctrl_is_inactive(struct uvc_video_chain *chain,
+ struct uvc_control *ctrl,
+ struct uvc_control_mapping *mapping)
+{
+ struct uvc_control_mapping *master_map = NULL;
+ struct uvc_control *master_ctrl = NULL;
+ s32 val;
+ int ret;
+
+ if (!mapping->master_id)
+ return false;
+
+ __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 false;
+
+ ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
+ if (ret < 0 || val == mapping->master_manual)
+ return false;
+
+ return true;
+}
+
static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
struct uvc_control *ctrl,
struct uvc_control_mapping *mapping,
struct v4l2_queryctrl *v4l2_ctrl)
{
- struct uvc_control_mapping *master_map = NULL;
- struct uvc_control *master_ctrl = NULL;
const struct uvc_menu_info *menu;
unsigned int i;

@@ -1126,18 +1149,8 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
v4l2_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;

- if (mapping->master_id)
- __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)) {
- s32 val;
- int ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
- if (ret < 0)
- return ret;
-
- if (val != mapping->master_manual)
- v4l2_ctrl->flags |= V4L2_CTRL_FLAG_INACTIVE;
- }
+ if (uvc_ctrl_is_inactive(chain, ctrl, mapping))
+ v4l2_ctrl->flags |= V4L2_CTRL_FLAG_INACTIVE;

if (!ctrl->cached) {
int ret = uvc_ctrl_populate_cache(chain, ctrl);
@@ -1660,25 +1673,37 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
return 0;
}

-static int uvc_ctrl_find_ctrl_idx(struct uvc_entity *entity,
- struct v4l2_ext_controls *ctrls,
- struct uvc_control *uvc_control)
+static int uvc_ctrl_commit_error(struct uvc_video_chain *chain,
+ struct uvc_entity *entity,
+ struct v4l2_ext_controls *ctrls,
+ struct uvc_control *err_control,
+ int ret)
{
struct uvc_control_mapping *mapping;
struct uvc_control *ctrl_found;
unsigned int i;

- if (!entity)
- return ctrls->count;
+ if (!entity) {
+ ctrls->error_idx = ctrls->count;
+ return ret;
+ }

for (i = 0; i < ctrls->count; i++) {
__uvc_find_control(entity, ctrls->controls[i].id, &mapping,
&ctrl_found, 0);
- if (uvc_control == ctrl_found)
- return i;
+ if (err_control == ctrl_found)
+ break;
}
+ ctrls->error_idx = i;
+
+ /* We could not find the control that failed. */
+ if (i == ctrls->count)
+ return ret;
+
+ if (uvc_ctrl_is_inactive(chain, err_control, mapping))
+ return -EACCES;

- return ctrls->count;
+ return ret;
}

int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
@@ -1701,8 +1726,8 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
uvc_ctrl_send_events(handle, ctrls->controls, ctrls->count);
done:
if (ret < 0 && ctrls)
- ctrls->error_idx = uvc_ctrl_find_ctrl_idx(entity, ctrls,
- err_ctrl);
+ ret = uvc_ctrl_commit_error(chain, entity, ctrls, err_ctrl,
+ ret);
mutex_unlock(&chain->ctrl_mutex);
return ret;
}
--
2.32.0.288.g62a8d224e6-goog
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