From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
To: Ricardo Ribalda <ribalda@chromium.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
tfiga@chromium.org
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Subject: Re: [PATCH v5 10/13] media: uvcvideo: Return -EACCES to inactive controls
Date: Wed, 17 Mar 2021 12:26:40 +0100 [thread overview]
Message-ID: <bf944318-3a20-e932-aaba-523025d19ad3@xs4all.nl> (raw)
In-Reply-To: <20210316180004.1605727-11-ribalda@chromium.org>
On 16/03/2021 19:00, Ricardo Ribalda 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.
>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> Suggested-by: Hans Verkuil <hverkuil@xs4all.nl>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index ba14733db757..98614e1be829 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1578,6 +1578,18 @@ int uvc_ctrl_begin(struct uvc_video_chain *chain)
> return mutex_lock_interruptible(&chain->ctrl_mutex) ? -ERESTARTSYS : 0;
> }
>
> +static bool uvc_ctrl_is_inactive(struct uvc_control *ctrl)
This doesn't test if the control is inactive, it tests if it *might* be
inactive. To test if it is really inactive would require checking the value
of the master control.
> +{
> + struct uvc_control_mapping *map;
> +
> + list_for_each_entry(map, &ctrl->info.mappings, list) {
> + if (map->master_id)
> + return true;
> + }
> +
> + return false;
> +}
> +
> static int uvc_ctrl_commit_entity(struct uvc_device *dev,
> struct uvc_entity *entity, int rollback)
> {
> @@ -1621,8 +1633,11 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
>
> ctrl->dirty = 0;
>
> - if (ret < 0)
> + if (ret < 0) {
> + if (uvc_ctrl_is_inactive(ctrl))
> + return -EACCES;
So here you assume that if setting the control failed, and if the control
might be inactive, then it probably was inactive.
I feel a bit uncomfortable by this assumption.
Regards,
Hans
> return ret;
> + }
> }
>
> return 0;
>
next prev parent reply other threads:[~2021-03-17 11:27 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 17:59 [PATCH v5 00/13] uvcvideo: Fix v4l2-compliance errors Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 01/13] media: v4l2-ioctl: Fix check_ext_ctrls Ricardo Ribalda
2021-03-17 10:36 ` Hans Verkuil
2021-03-16 17:59 ` [PATCH v5 02/13] media: uvcvideo: Set capability in s_param Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 03/13] media: uvcvideo: Return -EIO for control errors Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 04/13] media: uvcvideo: Check controls flags before accessing them Ricardo Ribalda
2021-03-17 10:50 ` Hans Verkuil
2021-03-16 17:59 ` [PATCH v5 05/13] media: uvcvideo: refactor __uvc_ctrl_add_mapping Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 06/13] media: uvcvideo: Add support for V4L2_CTRL_TYPE_CTRL_CLASS Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 07/13] media: uvcvideo: Use dev->name for querycap() Ricardo Ribalda
2021-03-17 10:57 ` Hans Verkuil
2021-03-16 17:59 ` [PATCH v5 08/13] media: uvcvideo: Set unique vdev name based in type Ricardo Ribalda
2021-03-16 17:59 ` [PATCH v5 09/13] media: uvcvideo: Increase the size of UVC_METADATA_BUF_SIZE Ricardo Ribalda
2021-03-17 11:01 ` Hans Verkuil
2021-03-16 18:00 ` [PATCH v5 10/13] media: uvcvideo: Return -EACCES to inactive controls Ricardo Ribalda
2021-03-17 11:26 ` Hans Verkuil [this message]
2021-03-16 18:00 ` [PATCH v5 11/13] media: uvcvideo: Use control names from framework Ricardo Ribalda
2021-03-17 11:29 ` Hans Verkuil
2021-03-16 18:00 ` [PATCH v5 12/13] media: v4l2-ioctl: Set error_idx to the right value Ricardo Ribalda
2021-03-17 11:39 ` Hans Verkuil
2021-03-16 18:00 ` [PATCH v5 13/13] uvc: use vb2 ioctl and fop helpers Ricardo Ribalda
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