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Subject: Re: [PATCH v10 21/21] media: uvcvideo: Return -EACCES to inactive
 controls
To:     Ricardo Ribalda <ribalda@chromium.org>
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
References: <20210618122923.385938-1-ribalda@chromium.org>
 <20210618122923.385938-22-ribalda@chromium.org>
 <CANiDSCvNvJ_xyuqgvvFv6aZGSm=H-9=SeV6wp5C_0-acm+wC=A@mail.gmail.com>
 <820809c2-a564-8a79-c279-7570c3bcc801@xs4all.nl>
 <CANiDSCvwQvDYKNqxAZjtAKY6CGNrnn21LMoNnsg7FrrDiooi-A@mail.gmail.com>
 <d65ab386-370e-b2e9-dbac-a981993d9da7@xs4all.nl>
 <CANiDSCv=FMy6g1aQhVRxH1tADSyLAOAY7csMwPFtXZVMU8N6VA@mail.gmail.com>
From:   Hans Verkuil <hverkuil-cisco@xs4all.nl>
Message-ID: <1157542d-7088-fe70-965a-cfa128090bb3@xs4all.nl>
Date:   Tue, 6 Jul 2021 16:18:37 +0200
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On 30/06/2021 14:51, Ricardo Ribalda wrote:
> 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

I tried with and without this patch and I didn't see any difference. Unfortunately,
I don't remember the exact details of what I tested last time and with which hardware.

I would drop this patch, it can always be added later.

Regards,

	Hans

> 
> 
> 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
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>>
>>
> 
>