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Message-ID: <CANiDSCu2__2Ta6BcF24DC=+Cir1aO=QF5xsVK4-vkephbAXiSg@mail.gmail.com>
Date: Fri, 19 Mar 2021 10:49:19 +0100
From: Ricardo Ribalda <ribalda@...omium.org>
To: Hans Verkuil <hverkuil-cisco@...all.nl>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Linux Media Mailing List <linux-media@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Tomasz Figa <tfiga@...omium.org>
Subject: Re: [PATCH v7 13/17] media: uvcvideo: Return -EACCES to inactive controls
Hi Hans
Thanks for testing this.
On Fri, Mar 19, 2021 at 10:10 AM Hans Verkuil <hverkuil-cisco@...all.nl> wrote:
>
> On 18/03/2021 21:29, 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.
> >
> > Reviewed-by: Hans Verkuil <hverkuil-cisco@...all.nl>
> > Suggested-by: Hans Verkuil <hverkuil-cisco@...all.nl>
> > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> > ---
> > drivers/media/usb/uvc/uvc_ctrl.c | 68 ++++++++++++++++++++++----------
> > drivers/media/usb/uvc/uvc_v4l2.c | 11 +++++-
> > drivers/media/usb/uvc/uvcvideo.h | 2 +-
> > 3 files changed, 58 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 24fd5afc4e4f..1ec8333811bc 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -1046,8 +1046,33 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
> > return 0;
> > }
> >
> > +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;
> > +}
>
> This doesn't work. The problem is that you need to test the new value for the
> master control against master_manual, and you are testing against the old value.
>
> So for my uvc camera I have this situation after boot:
>
> auto_exposure 0x009a0901 (menu) : min=0 max=3 default=3 value=3 (Aperture Priority Mode)
> 1: Manual Mode
> 3: Aperture Priority Mode
> exposure_time_absolute 0x009a0902 (int) : min=3 max=2047 step=1 default=250 value=250 flags=inactive
>
> But trying to change both auto_exposure to manual AND set the new exposure_time_absolute
> will fail:
>
> $ v4l2-ctl -c auto_exposure=1,exposure_time_absolute=251
> VIDIOC_S_EXT_CTRLS: failed: Permission denied
> Error setting controls: Permission denied
>
> This works though with the uvc driver as is currently in the kernel.
>
> Unfortunately, this is not something that is explicitly tested in v4l2-compliance.
>
Can you try dropping this patch and relaying on media: uvcvideo: Set
error_idx during ctrl_commit errors ?
thanks!
> Regards,
>
> Hans
>
> > +
> > int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> > - bool read)
> > + unsigned long ioctl)
> > {
> > struct uvc_control_mapping *mapping;
> > struct uvc_control *ctrl;
> > @@ -1059,11 +1084,26 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> > if (!ctrl)
> > return -EINVAL;
> >
> > - if (!(ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR) && read)
> > - return -EACCES;
> > -
> > - if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read)
> > - return -EACCES;
> > + switch (ioctl) {
> > + case VIDIOC_G_CTRL:
> > + case VIDIOC_G_EXT_CTRLS:
> > + if (!(ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR))
> > + return -EACCES;
> > + break;
> > + case VIDIOC_S_EXT_CTRLS:
> > + case VIDIOC_S_CTRL:
> > + if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
> > + return -EACCES;
> > + if (uvc_ctrl_is_inactive(chain, ctrl, mapping))
> > + return -EACCES;
> > + break;
> > + case VIDIOC_TRY_EXT_CTRLS:
> > + if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR))
> > + return -EACCES;
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> >
> > return 0;
> > }
> > @@ -1087,8 +1127,6 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> > 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;
> >
> > @@ -1104,18 +1142,8 @@ 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);
> > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> > index fbb99f3c2fb4..ddebdeb5a81b 100644
> > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > @@ -999,6 +999,10 @@ static int uvc_ioctl_g_ctrl(struct file *file, void *fh,
> > struct v4l2_ext_control xctrl;
> > int ret;
> >
> > + ret = uvc_ctrl_is_accessible(chain, ctrl->id, VIDIOC_G_CTRL);
> > + if (ret)
> > + return ret;
> > +
> > memset(&xctrl, 0, sizeof(xctrl));
> > xctrl.id = ctrl->id;
> >
> > @@ -1023,6 +1027,10 @@ static int uvc_ioctl_s_ctrl(struct file *file, void *fh,
> > struct v4l2_ext_control xctrl;
> > int ret;
> >
> > + ret = uvc_ctrl_is_accessible(chain, ctrl->id, VIDIOC_S_CTRL);
> > + if (ret)
> > + return ret;
> > +
> > memset(&xctrl, 0, sizeof(xctrl));
> > xctrl.id = ctrl->id;
> > xctrl.value = ctrl->value;
> > @@ -1054,8 +1062,7 @@ 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, ioctl);
> > if (ret)
> > break;
> > }
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 9471c342a310..a93aeedb5499 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -903,7 +903,7 @@ 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);
> > + unsigned long ioctl);
> >
> > int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
> > struct uvc_xu_control_query *xqry);
> >
>
--
Ricardo Ribalda
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