Re: [PATCH v7 4/7] media: uvcvideo: implement UVC v1.5 ROI

Yunke Cao
2022-08-29T05:48:44Z

Hi Laurent,

Thanks for the review!

On Thu, Aug 25, 2022 at 5:37 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Yunke,
>
> Thank you for the patch.
>
> On Tue, Jun 28, 2022 at 04:57:02PM +0900, Yunke Cao wrote:
> > Implement support for ROI as described in UVC 1.5:
> > 4.2.2.1.20 Digital Region of Interest (ROI) Control
> >
> > ROI control is implemented using V4L2 control API as
> > two uvc-specific controls:
>
> s/uvc/UVC/
>
> > V4L2_CID_UVC_REGION_OF_INTEREST_RECT and
> > V4L2_CID_UVC_REGION_OF_INTEREST_AUTO.
> >
> > Signed-off-by: Yunke Cao <yunkec@google.com>
> > ---
> > drivers/media/usb/uvc/uvc_ctrl.c | 146 ++++++++++++++++++++++++++++-
> > drivers/media/usb/uvc/uvc_v4l2.c | 5 +-
> > drivers/media/usb/uvc/uvcvideo.h | 7 ++
> > include/uapi/linux/usb/video.h | 1 +
> > include/uapi/linux/uvcvideo.h | 13 +++
> > include/uapi/linux/v4l2-controls.h | 8 ++
> > 6 files changed, 178 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 508ee04afbcd..00482269233a 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -355,6 +355,23 @@ static const struct uvc_control_info uvc_ctrls[] = {
> > .flags = UVC_CTRL_FLAG_GET_CUR
> > | UVC_CTRL_FLAG_AUTO_UPDATE,
> > },
> > + /* UVC_CTRL_FLAG_AUTO_UPDATE is needed because the RoI may get updated
>
> /*
> * UVC_CTRL_...
>
> > + * by sensors.
> > + * "This RoI should be the same as specified in most recent SET_CUR
> > + * except in the case where the ‘Auto Detect and Track’ and/or
> > + * ‘Image Stabilization’ bit have been set."
> > + * 4.2.2.1.20 Digital Region of Interest (ROI) Control
> > + */
> > + {
> > + .entity = UVC_GUID_UVC_CAMERA,
> > + .selector = UVC_CT_REGION_OF_INTEREST_CONTROL,
> > + .index = 21,
> > + .size = 10,
> > + .flags = UVC_CTRL_FLAG_SET_CUR | UVC_CTRL_FLAG_GET_CUR
> > + | UVC_CTRL_FLAG_GET_MIN | UVC_CTRL_FLAG_GET_MAX
> > + | UVC_CTRL_FLAG_GET_DEF
> > + | UVC_CTRL_FLAG_AUTO_UPDATE,
> > + },
> > };
> >
> > static const u32 uvc_control_classes[] = {
> > @@ -429,6 +446,64 @@ static void uvc_ctrl_set_rel_speed(struct uvc_control_mapping *mapping,
> > data[first+1] = min_t(int, abs(value), 0xff);
> > }
> >
> > +static void uvc_to_v4l2_rect(struct v4l2_rect *v4l2_rect,
> > + const struct uvc_rect *uvc_rect)
> > +{
> > + v4l2_rect->top = uvc_rect->top;
> > + v4l2_rect->left = uvc_rect->left;
> > + v4l2_rect->height = uvc_rect->bottom - uvc_rect->top + 1;
> > + v4l2_rect->width = uvc_rect->right - uvc_rect->left + 1;
>
> What happens if the device sends a bogus value with top > bottom or left
> > right ?
>

Hmm. I didn't think of this. I guess we should check and return -EINVAL.

> > +}
> > +
> > +static int v4l2_to_uvc_rect(struct uvc_rect *uvc_rect,
> > + const struct v4l2_rect *v4l2_rect)
> > +{
> > + // Safely converts s32 and u32 to u16.
>
> C-style comments.
>
> > + if (v4l2_rect->top > U16_MAX || v4l2_rect->top < 0 ||
> > + v4l2_rect->left > U16_MAX || v4l2_rect->left < 0 ||
> > + v4l2_rect->height > U16_MAX || v4l2_rect->height == 0 ||
> > + v4l2_rect->width > U16_MAX || v4l2_rect->width == 0 ||
> > + v4l2_rect->height + v4l2_rect->top - 1 > U16_MAX ||
> > + v4l2_rect->width + v4l2_rect->left - 1 > U16_MAX)
> > + return -ERANGE;
>
> Doesn't V4L2 adjust the control value instead ?
>

videoc-g-ext-ctrls.rst says
" When the value is out of bounds drivers can choose to take the closest
valid value or return an ERANGE error code, whatever seems more appropriate."

I chose to return ERANGE because it's a bit easier. Is it acceptable?

> > +
> > + uvc_rect->top = v4l2_rect->top;
> > + uvc_rect->left = v4l2_rect->left;
> > + uvc_rect->bottom = v4l2_rect->height + v4l2_rect->top - 1;
> > + uvc_rect->right = v4l2_rect->width + v4l2_rect->left - 1;
> > + return 0;
> > +}
> > +
> > +static int uvc_get_array_rect(struct uvc_control_mapping *mapping,
> > + const u8 *data, u8 *data_out)
> > +{
> > + struct uvc_rect *uvc_rect;
> > +
> > + if (WARN_ON(mapping->offset % 8 || mapping->size % 8))
> > + return -EINVAL;
> > + if (WARN_ON(mapping->size / 8 != sizeof(struct uvc_rect)))
> > + return -EINVAL;
> > +
>
> These checks should go to mapping creation time.
>
> > + uvc_rect = (struct uvc_rect *)(data + mapping->offset / 8);
>
> If the offset happens to not be a multiple of 2 bytes this will cause
> unaligned accesses on some platforms.
>
> > + uvc_to_v4l2_rect((struct v4l2_rect *)data_out, uvc_rect);
>
> Same here if not aligned on 4 bytes.
>
> > +
> > + return 0;
> > +}
> > +
> > +static int uvc_set_array_rect(struct uvc_control_mapping *mapping,
> > + const u8 *data_in, u8 *data)
> > +{
> > + struct uvc_rect *uvc_rect;
> > +
> > + if (WARN_ON(mapping->offset % 8 || mapping->size % 8))
> > + return -EINVAL;
> > + if (WARN_ON(mapping->size / 8 != sizeof(struct uvc_rect)))
> > + return -EINVAL;
> > +
>
> Same here.
>
> > + uvc_rect = (struct uvc_rect *)(data + mapping->offset / 8);
> > + return v4l2_to_uvc_rect(uvc_rect, (struct v4l2_rect *)data_in);
> > +}
> > +
> > static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> > {
> > .id = V4L2_CID_BRIGHTNESS,
> > @@ -728,6 +803,26 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> > .v4l2_type = V4L2_CTRL_TYPE_BOOLEAN,
> > .data_type = UVC_CTRL_DATA_TYPE_BOOLEAN,
> > },
> > + {
> > + .id = V4L2_CID_UVC_REGION_OF_INTEREST_RECT,
> > + .entity = UVC_GUID_UVC_CAMERA,
> > + .selector = UVC_CT_REGION_OF_INTEREST_CONTROL,
> > + .size = 64,
>
> sizeof(struct uvc_rect)
>
> > + .offset = 0,
> > + .v4l2_type = V4L2_CTRL_TYPE_RECT,
> > + .data_type = UVC_CTRL_DATA_TYPE_RECT,
> > + .get_array = uvc_get_array_rect,
> > + .set_array = uvc_set_array_rect,
> > + },
> > + {
> > + .id = V4L2_CID_UVC_REGION_OF_INTEREST_AUTO,
> > + .entity = UVC_GUID_UVC_CAMERA,
> > + .selector = UVC_CT_REGION_OF_INTEREST_CONTROL,
> > + .size = 16,
> > + .offset = 64,
> > + .v4l2_type = V4L2_CTRL_TYPE_BITMASK,
> > + .data_type = UVC_CTRL_DATA_TYPE_BITMASK,
> > + },
> > };
> >
> > /* ------------------------------------------------------------------------
> > @@ -1061,7 +1156,16 @@ static int __uvc_ctrl_get_compound_to_user(struct uvc_control_mapping *mapping,
> > if (WARN_ON(!mapping->size % 8))
> > return -EINVAL;
> >
> > - size = mapping->size / 8;
> > + switch (mapping->v4l2_type) {
> > + case V4L2_CTRL_TYPE_RECT:
> > + size = sizeof(struct v4l2_rect);
>
> Oohhh that sounds fragile. I'm worried we may be using mapping->size as
> the V4L2 control size somewhere else.
>
> It would be safer to split the size field of uvc_control_mapping into a
> v4l2_size and a uvc_size (or possibly data_size to match the v4l2_type
> and data_type names) in a patch before this. This will force reviewing
> all the users of the size field to check which size they need.
>

Thanks for the suggestion! That makes a lot of sense. I will try to implement
this in the next version, and fix other places you pointed out.

Best,
Yunke

> > + break;
> > +
> > + default:
> > + size = mapping->size / 8;
> > + break;
> > + }
> > +
> > if (xctrl->size < size) {
> > xctrl->size = size;
> > return -ENOSPC;
> > @@ -2578,6 +2682,40 @@ static void uvc_ctrl_prune_entity(struct uvc_device *dev,
> > }
> > }
> >
> > +static int uvc_ctrl_init_roi(struct uvc_device *dev, struct uvc_control *ctrl)
> > +{
> > + int ret;
> > +
> > + ret = uvc_query_ctrl(dev, UVC_GET_DEF, ctrl->entity->id, dev->intfnum,
> > + UVC_CT_REGION_OF_INTEREST_CONTROL,
> > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF),
> > + ctrl->info.size);
> > + if (ret)
> > + goto out;
> > +
> > + /*
> > + * Most firmwares have wrong GET_CURRENT configuration. E.g. it's
>
> s/GET_CURRENT/GET_CUR/
>
> > + * below GET_MIN, or have rectangle coordinates mixed up. This
> > + * causes problems sometimes, because we are unable to set
> > + * auto-controls value without first setting ROI rectangle to
> > + * valid configuration.
> > + *
> > + * We expect that default configuration is always correct and
> > + * is within the GET_MIN / GET_MAX boundaries.
>
> A dangerous expectation to make given the quality of most UVC camera
> firmwares...
>
> > + *
> > + * Set current ROI configuration to GET_DEF, so that we will
> > + * always have properly configured ROI.
> > + */
> > + ret = uvc_query_ctrl(dev, UVC_SET_CUR, 1, dev->intfnum,
> > + UVC_CT_REGION_OF_INTEREST_CONTROL,
> > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF),
> > + ctrl->info.size);
> > +out:
> > + if (ret)
> > + dev_err(&dev->udev->dev, "Failed to fixup ROI (%d).\n", ret);
>
> s/(%d)./(%d)/
>
> > + return ret;
> > +}
> > +
> > /*
> > * Add control information and hardcoded stock control mappings to the given
> > * device.
> > @@ -2590,6 +2728,7 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
> > const struct uvc_control_mapping *mapping = uvc_ctrl_mappings;
> > const struct uvc_control_mapping *mend =
> > mapping + ARRAY_SIZE(uvc_ctrl_mappings);
> > + const u8 camera_entity[16] = UVC_GUID_UVC_CAMERA;
> >
> > /* XU controls initialization requires querying the device for control
> > * information. As some buggy UVC devices will crash when queried
> > @@ -2610,6 +2749,11 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
> > * GET_INFO on standard controls.
> > */
> > uvc_ctrl_get_flags(chain->dev, ctrl, &ctrl->info);
> > +
> > + if (ctrl->info.selector ==
> > + UVC_CT_REGION_OF_INTEREST_CONTROL &&
> > + uvc_entity_match_guid(ctrl->entity, camera_entity))
> > + uvc_ctrl_init_roi(chain->dev, ctrl);
>
> Should we instead add an init operation to the uvc_control_info
> structure ?
>
> > break;
> > }
> > }
> > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> > index 0366d05895a9..aad61af36271 100644
> > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > @@ -998,7 +998,10 @@ static int uvc_ioctl_query_ext_ctrl(struct file *file, void *fh,
> > qec->step = qc.step;
> > qec->default_value = qc.default_value;
> > qec->flags = qc.flags;
> > - qec->elem_size = 4;
> > + if (qc.type == V4L2_CTRL_TYPE_RECT)
> > + qec->elem_size = sizeof(struct v4l2_rect);
> > + else
> > + qec->elem_size = 4;
> > qec->elems = 1;
> > qec->nr_of_dims = 0;
> > memset(qec->dims, 0, sizeof(qec->dims));
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 2f9b75faae83..9ff95bbad251 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -431,6 +431,13 @@ struct uvc_streaming_header {
> > u8 bTriggerUsage;
> > };
> >
> > +struct uvc_rect {
> > + u16 top;
> > + u16 left;
> > + u16 bottom;
> > + u16 right;
> > +} __packed;
> > +
> > enum uvc_buffer_state {
> > UVC_BUF_STATE_IDLE = 0,
> > UVC_BUF_STATE_QUEUED = 1,
> > diff --git a/include/uapi/linux/usb/video.h b/include/uapi/linux/usb/video.h
> > index bfdae12cdacf..9076a444758a 100644
> > --- a/include/uapi/linux/usb/video.h
> > +++ b/include/uapi/linux/usb/video.h
> > @@ -104,6 +104,7 @@
> > #define UVC_CT_ROLL_ABSOLUTE_CONTROL 0x0f
> > #define UVC_CT_ROLL_RELATIVE_CONTROL 0x10
> > #define UVC_CT_PRIVACY_CONTROL 0x11
> > +#define UVC_CT_REGION_OF_INTEREST_CONTROL 0x14
> >
> > /* A.9.5. Processing Unit Control Selectors */
> > #define UVC_PU_CONTROL_UNDEFINED 0x00
> > diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h
> > index 8288137387c0..e2feee15cb1b 100644
> > --- a/include/uapi/linux/uvcvideo.h
> > +++ b/include/uapi/linux/uvcvideo.h
> > @@ -16,6 +16,7 @@
> > #define UVC_CTRL_DATA_TYPE_BOOLEAN 3
> > #define UVC_CTRL_DATA_TYPE_ENUM 4
> > #define UVC_CTRL_DATA_TYPE_BITMASK 5
> > +#define UVC_CTRL_DATA_TYPE_RECT 6
> >
> > /* Control flags */
> > #define UVC_CTRL_FLAG_SET_CUR (1 << 0)
> > @@ -36,6 +37,18 @@
> > UVC_CTRL_FLAG_GET_MAX | UVC_CTRL_FLAG_GET_RES | \
> > UVC_CTRL_FLAG_GET_DEF)
> >
> > +/* V4L2 private controls */
> > +#define V4L2_CID_UVC_REGION_OF_INTEREST_RECT (V4L2_CID_CAMERA_UVC_BASE + 1)
> > +#define V4L2_CID_UVC_REGION_OF_INTEREST_AUTO (V4L2_CID_CAMERA_UVC_BASE + 2)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_EXPOSURE (1 << 0)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_IRIS (1 << 1)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_WHITE_BALANCE (1 << 2)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_FOCUS (1 << 3)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_FACE_DETECT (1 << 4)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_DETECT_AND_TRACK (1 << 5)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_IMAGE_STABILIZATION (1 << 6)
> > +#define V4L2_UVC_REGION_OF_INTEREST_AUTO_HIGHER_QUALITY (1 << 7)
> > +
> > struct uvc_menu_info {
> > __u32 value;
> > __u8 name[32];
> > diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> > index dfff69ed88f7..d85be46e46f2 100644
> > --- a/include/uapi/linux/v4l2-controls.h
> > +++ b/include/uapi/linux/v4l2-controls.h
> > @@ -1013,6 +1013,14 @@ enum v4l2_auto_focus_range {
> >
> > #define V4L2_CID_CAMERA_SENSOR_ROTATION (V4L2_CID_CAMERA_CLASS_BASE+35)
> >
> > +/* CAMERA-class private control IDs */
> > +
>
> Why doesn't this go in the driver-specific controls range ?
>
> > +/*
> > + * The base for the uvc driver controls. See linux/uvcvideo.h for the list
> > + * of controls. We reserve 16 controls for this driver.
>
> I'd reserve more just in case, UVC 1.5 has quite a few controls that may
> not be exposed through standard V4L2 controls, especially for encoding
> units.
>
> > + */
> > +#define V4L2_CID_CAMERA_UVC_BASE (V4L2_CID_CAMERA_CLASS_BASE + 0x1000)
> > +
> > /* FM Modulator class control IDs */
> >
> > #define V4L2_CID_FM_TX_CLASS_BASE (V4L2_CTRL_CLASS_FM_TX | 0x900)
>
> --
> Regards,
>
> Laurent Pinchart