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

From: Ricardo Ribalda <ribalda@chromium.org>
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Hans Verkuil <hverkuil@xs4all.nl>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, tfiga@chromium.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 21/21] media: uvcvideo: Return -EACCES to inactive controls
Date: Wed, 30 Jun 2021 14:51:23 +0200	[thread overview]
Message-ID: <CANiDSCv=FMy6g1aQhVRxH1tADSyLAOAY7csMwPFtXZVMU8N6VA@mail.gmail.com> (raw)
In-Reply-To: <d65ab386-370e-b2e9-dbac-a981993d9da7@xs4all.nl>

Hi Hans

On Wed, 30 Jun 2021 at 11:03, Hans Verkuil <hverkuil-cisco@xs4all.nl> wrote:
>
> 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@xs4all.nl> 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@xs4all.nl>

Thanks a lot for testing it!

Sorry to bother you, but could I ask you to try again, but with this
patch reverted? This is v10 1-20, without 21/21

Thanks!
>
> 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@chromium.org> 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@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
> >>>>
> >>>
> >>>
> >>
> >
> >
>

-- 
Ricardo Ribalda