Re: [PATCH v4 06/11] media: uvcvideo: Add support for V4L2_CTRL_TYPE_CTRL_CLASS

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Hans,

On Tue, Mar 16, 2021 at 09:37:07AM +0100, Hans Verkuil wrote:
> On 15/03/2021 18:36, Ricardo Ribalda wrote:
> > Create all the class controls for the device defined controls.
> > 
> > Fixes v4l2-compliance:
> > Control ioctls (Input 0):
> > 		fail: v4l2-test-controls.cpp(216): missing control class for class 00980000
> > 		fail: v4l2-test-controls.cpp(216): missing control tclass for class 009a0000
> > 	test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: FAIL
> > 
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> >  drivers/media/usb/uvc/uvc_ctrl.c | 96 ++++++++++++++++++++++++++++++++
> >  drivers/media/usb/uvc/uvcvideo.h |  6 ++
> >  2 files changed, 102 insertions(+)
> > 
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index b75da65115ef..be0fadaf414c 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -357,6 +357,17 @@ static const struct uvc_control_info uvc_ctrls[] = {
> >  	},
> >  };
> >  
> > +static const struct uvc_control_class uvc_control_class[] = {
> > +	{
> > +		.id		= V4L2_CID_CAMERA_CLASS,
> > +		.name		= "Camera Controls",
> > +	},
> > +	{
> > +		.id		= V4L2_CID_USER_CLASS,
> > +		.name		= "User Controls",
> 
> I noticed that uvc_ctrl.c has hardcoded strings for the control names and
> control menus.
> 
> It would be good to drop that from the code and instead use v4l2_ctrl_get_menu()
> and v4l2_ctrl_get_name() to obtain the names. It ensures consistent naming and
> saves a bit of memory.
> 
> This can be done in a separate patch before or after this one.

https://git.linuxtv.org/pinchartl/media.git/commit/?h=uvc/dev&id=16a7d79d67cdd06a448d8c4c20e270d1c21828b1

It's work in progress, the part that bothers me is the changes in
uvc_parse_format(). We lose the human-readable name in a debug message,
but maybe more importantly, we lose the distinction between different DV
formats. Maybe it's not a big deal.

> > +	},
> > +};
> > +
> >  static const struct uvc_menu_info power_line_frequency_controls[] = {
> >  	{ 0, "Disabled" },
> >  	{ 1, "50 Hz" },
> > @@ -1024,6 +1035,49 @@ static int __uvc_ctrl_get(struct uvc_video_chain *chain,
> >  	return 0;
> >  }
> >  
> > +static int __uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
> > +				  u32 found_id)
> > +{
> > +	bool find_next = req_id & V4L2_CTRL_FLAG_NEXT_CTRL;
> > +	unsigned int i;
> > +
> > +	req_id &= V4L2_CTRL_ID_MASK;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(uvc_control_class); i++) {
> > +		if (!(chain->ctrl_class_bitmap & BIT(i)))
> > +			continue;
> > +		if (!find_next) {
> > +			if (uvc_control_class[i].id == req_id)
> > +				return i;
> > +			continue;
> > +		}
> > +		if (uvc_control_class[i].id > req_id &&
> > +		    uvc_control_class[i].id < found_id)
> > +			return i;
> > +	}
> > +
> > +	return -ENODEV;
> > +}
> > +
> > +static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id,
> > +				u32 found_id, struct v4l2_queryctrl *v4l2_ctrl)
> > +{
> > +	int idx;
> > +
> > +	idx = __uvc_query_v4l2_class(chain, req_id, found_id);
> > +	if (idx < 0)
> > +		return -ENODEV;
> > +
> > +	memset(v4l2_ctrl, 0, sizeof(*v4l2_ctrl));
> > +	v4l2_ctrl->id = uvc_control_class[idx].id;
> > +	strscpy(v4l2_ctrl->name, uvc_control_class[idx].name,
> > +		sizeof(v4l2_ctrl->name));
> > +	v4l2_ctrl->type = V4L2_CTRL_TYPE_CTRL_CLASS;
> > +	v4l2_ctrl->flags = V4L2_CTRL_FLAG_WRITE_ONLY
> > +			   | V4L2_CTRL_FLAG_READ_ONLY;
> > +	return 0;
> > +}
> > +
> >  static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> >  	struct uvc_control *ctrl,
> >  	struct uvc_control_mapping *mapping,
> > @@ -1127,12 +1181,31 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> >  	if (ret < 0)
> >  		return -ERESTARTSYS;
> >  
> > +	/* Check if the ctrl is a know class */
> > +	if (!(v4l2_ctrl->id & V4L2_CTRL_FLAG_NEXT_CTRL)) {
> > +		ret = uvc_query_v4l2_class(chain, v4l2_ctrl->id, 0, v4l2_ctrl);
> > +		if (!ret)
> > +			goto done;
> > +	}
> > +
> >  	ctrl = uvc_find_control(chain, v4l2_ctrl->id, &mapping);
> >  	if (ctrl == NULL) {
> >  		ret = -EINVAL;
> >  		goto done;
> >  	}
> >  
> > +	/*
> > +	 * If we're enumerating control with V4L2_CTRL_FLAG_NEXT_CTRL, check if
> > +	 * a class should be inserted between the previous control and the one
> > +	 * we have just found.
> > +	 */
> > +	if (v4l2_ctrl->id & V4L2_CTRL_FLAG_NEXT_CTRL) {
> > +		ret = uvc_query_v4l2_class(chain, v4l2_ctrl->id, mapping->id,
> > +					   v4l2_ctrl);
> > +		if (!ret)
> > +			goto done;
> > +	}
> > +
> >  	ret = __uvc_query_v4l2_ctrl(chain, ctrl, mapping, v4l2_ctrl);
> >  done:
> >  	mutex_unlock(&chain->ctrl_mutex);
> > @@ -1426,6 +1499,11 @@ static int uvc_ctrl_add_event(struct v4l2_subscribed_event *sev, unsigned elems)
> >  	if (ret < 0)
> >  		return -ERESTARTSYS;
> >  
> > +	if (__uvc_query_v4l2_class(handle->chain, sev->id, 0) >= 0) {
> > +		ret = 0;
> > +		goto done;
> > +	}
> > +
> >  	ctrl = uvc_find_control(handle->chain, sev->id, &mapping);
> >  	if (ctrl == NULL) {
> >  		ret = -EINVAL;
> > @@ -1459,7 +1537,10 @@ static void uvc_ctrl_del_event(struct v4l2_subscribed_event *sev)
> >  	struct uvc_fh *handle = container_of(sev->fh, struct uvc_fh, vfh);
> >  
> >  	mutex_lock(&handle->chain->ctrl_mutex);
> > +	if (__uvc_query_v4l2_class(handle->chain, sev->id, 0) >= 0)
> > +		goto done;
> >  	list_del(&sev->node);
> > +done:
> >  	mutex_unlock(&handle->chain->ctrl_mutex);
> >  }
> >  
> > @@ -1577,6 +1658,9 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
> >  	struct uvc_control *ctrl;
> >  	struct uvc_control_mapping *mapping;
> >  
> > +	if (__uvc_query_v4l2_class(chain, xctrl->id, 0) >= 0)
> > +		return -EACCES;
> > +
> >  	ctrl = uvc_find_control(chain, xctrl->id, &mapping);
> >  	if (ctrl == NULL)
> >  		return -EINVAL;
> > @@ -1596,6 +1680,9 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> >  	s32 max;
> >  	int ret;
> >  
> > +	if (__uvc_query_v4l2_class(chain, xctrl->id, 0) >= 0)
> > +		return -EACCES;
> > +
> >  	ctrl = uvc_find_control(chain, xctrl->id, &mapping);
> >  	if (ctrl == NULL)
> >  		return -EINVAL;
> > @@ -2062,6 +2149,7 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> >  {
> >  	struct uvc_control_mapping *map;
> >  	unsigned int size;
> > +	unsigned int i;
> >  
> >  	/* Most mappings come from static kernel data and need to be duplicated.
> >  	 * Mappings that come from userspace will be unnecessarily duplicated,
> > @@ -2085,6 +2173,14 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> >  	if (map->set == NULL)
> >  		map->set = uvc_set_le_value;
> >  
> > +	for (i = 0; i < ARRAY_SIZE(uvc_control_class); i++) {
> > +		if (V4L2_CTRL_ID2WHICH(uvc_control_class[i].id) ==
> > +						V4L2_CTRL_ID2WHICH(map->id)) {
> > +			chain->ctrl_class_bitmap |= BIT(i);
> > +			break;
> > +		}
> > +	}
> > +
> >  	list_add_tail(&map->list, &ctrl->info.mappings);
> >  	uvc_dbg(chain->dev, CONTROL, "Adding mapping '%s' to control %pUl/%u\n",
> >  		map->name, ctrl->info.entity, ctrl->info.selector);
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 97df5ecd66c9..1f17e4253673 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -262,6 +262,11 @@ struct uvc_control_mapping {
> >  		    u8 *data);
> >  };
> >  
> > +struct uvc_control_class {
> > +	u32 id;
> > +	char name[32];
> > +};
> > +
> >  struct uvc_control {
> >  	struct uvc_entity *entity;
> >  	struct uvc_control_info info;
> > @@ -475,6 +480,7 @@ struct uvc_video_chain {
> >  
> >  	struct v4l2_prio_state prio;		/* V4L2 priority state */
> >  	u32 caps;				/* V4L2 chain-wide caps */
> > +	u8 ctrl_class_bitmap;			/* Bitmap of valid classes */
> >  };
> >  
> >  struct uvc_stats_frame {
> > 
> 

-- 
Regards,

Laurent Pinchart