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Message-ID: <Y63+nF2PqKad8S18@pendragon.ideasonboard.com>
Date: Thu, 29 Dec 2022 22:54:52 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Ricardo Ribalda <ribalda@...omium.org>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
Hans Verkuil <hverkuil@...all.nl>,
Hans Verkuil <hverkuil-cisco@...all.nl>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
Hans Verkuil <hans.verkuil@...co.com>
Subject: Re: [PATCH RESEND v2 1/7] media: uvcvideo: uvc_ctrl_is_accessible:
check for INACTIVE
Hi Ricardo and Hans,
Thank you for the patch.
On Fri, Dec 02, 2022 at 06:21:35PM +0100, Ricardo Ribalda wrote:
> From: Hans Verkuil <hverkuil@...all.nl>
>
> Check for inactive controls in uvc_ctrl_is_accessible().
> Use the new value for the master_id controls if present,
> otherwise use the existing value to determine if it is OK
> to set the control. Doing this here avoids attempting to
> set an inactive control, which will return an error from the
> USB device, which returns an invalid errorcode.
I'd write the subject line as
media: uvcvideo: Check for INACTIVE in uvc_ctrl_is_accessible()
and reflow the commit message to 72 columns here.
> This fixes:
> warn: v4l2-test-controls.cpp(483): s_ctrl returned EIO
> warn: v4l2-test-controls.cpp(483): s_ctrl returned EIO
> test VIDIOC_G/S_CTRL: OK
> warn: v4l2-test-controls.cpp(739): s_ext_ctrls returned EIO
> warn: v4l2-test-controls.cpp(739): s_ext_ctrls returned EIO
> warn: v4l2-test-controls.cpp(816): s_ext_ctrls returned EIO
> test VIDIOC_G/S/TRY_EXT_CTRLS: OK
>
> Tested with:
> v4l2-ctl -c auto_exposure=1
> OK
> v4l2-ctl -c exposure_time_absolute=251
> OK
> v4l2-ctl -c auto_exposure=3
> OK
> v4l2-ctl -c exposure_time_absolute=251
> VIDIOC_S_EXT_CTRLS: failed: Input/output error
> exposure_time_absolute: Input/output error
> ERROR
> v4l2-ctl -c auto_exposure=3,exposure_time_absolute=251,auto_exposure=1
> v4l2-ctl -C auto_exposure,exposure_time_absolute
> auto_exposure: 1
> exposure_time_absolute: 251
>
> Reviewed-by: Ricardo Ribalda <ribalda@...omium.org>
> Signed-off-by: Hans Verkuil <hans.verkuil@...co.com>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 47 +++++++++++++++++++++++++++++++++++++++-
> drivers/media/usb/uvc/uvc_v4l2.c | 4 ++--
> drivers/media/usb/uvc/uvcvideo.h | 3 ++-
> 3 files changed, 50 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 8c208db9600b..7153ee5aabb1 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1064,11 +1064,33 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
> return 0;
> }
>
> +/**
> + * uvc_ctrl_is_accessible() - Check if a control can be read/writen/tried.
> + * @chain: uvc_video_chain that the controls belong to.
> + * @v4l2_id: video4linux id of the control.
> + * @ctrl: Other controls that will be accessed in the ioctl.
> + * @ioctl: ioctl used to access the control.
The driver doesn't use kerneldoc anywhere, so to match the current style
I'd use /* instead of /**, and drop the documentation of the function
arguments as it's trivial.
> + *
> + * Check if a control can be accessed by a specicific ioctl operation,
s/specicific/specific/
> + * assuming that other controls are also going to be accessed by that ioctl.
> + * We need to check the value of the other controls, to support operations
> + * where a master value is changed with a slave value. Eg.
> + * auto_exposure=1,exposure_time_absolute=251
> + *
Extra blank line.
I'd rephrase that a bit to make it more precise:
* Check if control @v4l2_id can be accessed by the given control @ioctl
* (VIDIOC_G_EXT_CTRLS, VIDIOC_TRY_EXT_CTRLS or VIDIOC_S_EXT_CTRLS).
*
* For set operations on slave controls, check if the master's value is set to
* manual, either in the others controls set in the same ioctl call, or from the
* master's current value. This catches VIDIOC_S_EXT_CTRLS calls that
* set both the master and slave control, such as for instance setting
* auto_exposure=1,exposure_time_absolute=251.
> + */
> int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> - bool read)
> + const struct v4l2_ext_controls *ctrls,
> + unsigned long ioctl)
> {
> + struct uvc_control_mapping *master_map = NULL;
> + struct uvc_control *master_ctrl = NULL;
> struct uvc_control_mapping *mapping;
> struct uvc_control *ctrl;
> + bool read = ioctl == VIDIOC_G_EXT_CTRLS;
> + bool try = ioctl == VIDIOC_TRY_EXT_CTRLS;
> + s32 val;
> + int ret;
> + int i;
>
> if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0)
> return -EACCES;
> @@ -1083,6 +1105,29 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read)
> return -EACCES;
>
> + if (read || try || !mapping->master_id)
I'd write this
if (ioctl != VIDIOC_S_EXT_CTRLS || !mapping->master_id)
and drop the try variable.
> + return 0;
> +
> + /*
> + * Iterate backwards in cases where the master control is accessed
> + * multiple times in the same ioctl. We want the last value.
> + */
> + for (i = ctrls->count - 1; i >= 0; i--) {
> + if (ctrls->controls[i].id == mapping->master_id)
> + return ctrls->controls[i].value ==
> + mapping->master_manual ? 0 : -EACCES;
> + }
> +
> + __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 0;
> +
> + ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
> + if (ret >= 0 && val != mapping->master_manual)
> + return -EACCES;
> +
> return 0;
> }
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 4cc3fa6b8c98..d95168cdc2d1 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -1020,8 +1020,8 @@ static int uvc_ctrl_check_access(struct uvc_video_chain *chain,
> int ret = 0;
>
> for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_is_accessible(chain, ctrl->id,
> - ioctl == VIDIOC_G_EXT_CTRLS);
> + ret = uvc_ctrl_is_accessible(chain, ctrl->id, ctrls,
> + ioctl);
This holds on a single line.
Conditionally-Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
I can address all the review comments when applying.
> if (ret)
> break;
> }
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 24c911aeebce..644d5fcf2eef 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -905,7 +905,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle)
> int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);
> int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);
> int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> - bool read);
> + const struct v4l2_ext_controls *ctrls,
> + unsigned long ioctl);
>
> int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
> struct uvc_xu_control_query *xqry);
>
--
Regards,
Laurent Pinchart
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