Re: [PATCH v10 21/21] media: uvcvideo: Return -EACCES to inactive controls

[Hans Verkuil]

Hi Ricardo,

On 25/06/2021 15:55, Ricardo Ribalda wrote:
> Hi Hans
> 
> On Fri, 25 Jun 2021 at 13:07, Hans Verkuil <hverkuil-cisco@xxxxxxxxx> wrote:
>>
>> On 25/06/2021 12:29, Ricardo Ribalda wrote:
>>> Hi Hans
>>>
>>> Did you have some hardware that did not work fine without this patch?
>>> Am I remembering correctly?
>>
>> Yes, that's correct. It's one of my webcams, but I can't remember which one
>> it is. You probably want me to test this v10?
>>
>> Regards,
> 
> That would be awesome. Thanks!

You can add my:

Tested-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>

to this series.

I do get these warnings (depends on the webcam model, though, some do, some don't):

Streaming ioctls:
        test read/write: OK (Not Supported)
        test blocking wait: OK
                warn: v4l2-test-buffers.cpp(438): got sequence number 1, expected 0
        test MMAP (no poll): OK
                warn: v4l2-test-buffers.cpp(438): got sequence number 1, expected 0
        test MMAP (select): OK
                warn: v4l2-test-buffers.cpp(438): got sequence number 1, expected 0
        test MMAP (epoll): OK
                warn: v4l2-test-buffers.cpp(438): got sequence number 1, expected 0
        test USERPTR (no poll): OK
                warn: v4l2-test-buffers.cpp(438): got sequence number 1, expected 0
        test USERPTR (select): OK
        test DMABUF: Cannot test, specify --expbuf-device

It's something to do with the Field ID, but I'm not sure if this is really correctly
reporting a dropped frame, or if it is a false report and the sequence counter was
wrongly incremented.

This is a separate issue, though, and doesn't block this series.

Regards,

	Hans

> 
>>
>>         Hans
>>
>>>
>>> Thanks!
>>>
>>> On Fri, 18 Jun 2021 at 14:29, Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote:
>>>>
>>>> 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@xxxxxxxxx>
>>>> Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
>>>> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
>>>> ---
>>>>  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
>>>>
>>>
>>>
>>
> 
>