Hi Ricardo,

On Fri, Mar 12, 2021 at 10:57:33AM +0100, Ricardo Ribalda Delgado wrote:

On Fri, Mar 12, 2021 at 2:25 AM Laurent Pinchart wrote:

quoted

On Thu, Mar 11, 2021 at 11:19:45PM +0100, Ricardo Ribalda wrote:

quoted

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 <redacted>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 90 ++++++++++++++++++++++++++++++++
 drivers/media/usb/uvc/uvcvideo.h |  7 +++
 2 files changed, 97 insertions(+)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index b3dde98499f4..4e0ed2595ae9 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",
+     },
+};
+
 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_device *dev, u32 req_id,
+                               u32 found_id)
+{
+     bool find_next = req_id & V4L2_CTRL_FLAG_NEXT_CTRL;
+     int i;

unsigned int as i will never be negative.

Sometimes you are a bit negative with my patches... :)

(sorry, it is Friday)

quoted

quoted

+
+     req_id &= V4L2_CTRL_ID_MASK;
+
+     for (i = 0; i < ARRAY_SIZE(uvc_control_class); i++) {
+             if (!(dev->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))

No need for the inner parentheses.

quoted

+                     return i;
+     }
+
+     return -ENODEV;
+}
+
+static int uvc_query_v4l2_class(struct uvc_device *dev, u32 req_id,
+                             u32 found_id, struct v4l2_queryctrl *v4l2_ctrl)
+{
+     int idx;
+
+     idx = __uvc_query_v4l2_class(dev, 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;

        v4l2_ctrl->flags = V4L2_CTRL_FLAG_WRITE_ONLY
                         | V4L2_CTRL_FLAG_READ_ONLY;

quoted

+     return 0;
+}

If you agree with the comments below, you could inline
__uvc_query_v4l2_class() in uvc_query_v4l2_class() as it won't be called
separately.

quoted

+
 static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
      struct uvc_control *ctrl,
      struct uvc_control_mapping *mapping,

@@ -1123,6 +1177,14 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
      struct uvc_control_mapping *mapping;
      int ret;

+     /* Check if the ctrl is a know class */
+     if (!(v4l2_ctrl->id & V4L2_CTRL_FLAG_NEXT_CTRL)) {
+             ret = uvc_query_v4l2_class(chain->dev, v4l2_ctrl->id,
+                                        v4l2_ctrl->id, v4l2_ctrl);

You could pass 0 for found_id here.

quoted

+             if (!ret)
+                     return 0;
+     }
+

Should this be done with the chain->ctrl_mutex locked, as
__uvc_query_v4l2_class() accesses dev->ctrl_class_bitmap that could be
modified concurrently ?

quoted

      ret = mutex_lock_interruptible(&chain->ctrl_mutex);
      if (ret < 0)
              return -ERESTARTSYS;

@@ -1133,6 +1195,13 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
              goto done;
      }

A comment here along the lines of

        /*
         * 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.
         */

could be useful, as it's not trivial.

yes, it looks better thanks!

quoted

quoted

+     if (v4l2_ctrl->id & V4L2_CTRL_FLAG_NEXT_CTRL) {
+             ret = uvc_query_v4l2_class(chain->dev, 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);

@@ -1422,6 +1491,9 @@ static int uvc_ctrl_add_event(struct v4l2_subscribed_event *sev, unsigned elems)
      struct uvc_control *ctrl;
      int ret;

+     if (__uvc_query_v4l2_class(handle->chain->dev, sev->id, 0) >= 0)
+             return 0;

Do we really need to succeed ? What's the point in subscribing for
control change events on a class ? Can't we just check if sev->id is a
class, and return -EINVAL in that case ?

Unfortunately it is expected that you can subscribe to all the events,
even the ctrl_classes
        test VIDIOC_G/S/TRY_EXT_CTRLS: OK
                fail: v4l2-test-controls.cpp(835): subscribe event for
control 'User Controls' failed
        test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: FAIL

Looks like something that should be dropped from v4l2-compliance,
there's no use case for subscribing to a class.

quoted

quoted

+
      ret = mutex_lock_interruptible(&handle->chain->ctrl_mutex);
      if (ret < 0)
              return -ERESTARTSYS;

@@ -1458,6 +1530,9 @@ static void uvc_ctrl_del_event(struct v4l2_subscribed_event *sev)
 {
      struct uvc_fh *handle = container_of(sev->fh, struct uvc_fh, vfh);

+     if (__uvc_query_v4l2_class(handle->chain->dev, sev->id, 0) >= 0)
+             return;

And this could then be dropped, as this function won't be called if the
subscription failed.

quoted

+
      mutex_lock(&handle->chain->ctrl_mutex);
      list_del(&sev->node);
      mutex_unlock(&handle->chain->ctrl_mutex);

@@ -1577,6 +1652,9 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
      struct uvc_control *ctrl;
      struct uvc_control_mapping *mapping;

+     if (__uvc_query_v4l2_class(chain->dev, xctrl->id, 0) >= 0)
+             return -EACCES;
+
      ctrl = uvc_find_control(chain, xctrl->id, &mapping);
      if (ctrl == NULL)
              return -EINVAL;

@@ -1596,6 +1674,9 @@ int uvc_ctrl_set(struct uvc_fh *handle,
      s32 max;
      int ret;

+     if (__uvc_query_v4l2_class(chain->dev, xctrl->id, 0) >= 0)
+             return -EACCES;
+

Similarly as in patch 1/6, should these two checks be moved to
v4l_s_ctrl() and v4l_s_ext_ctrls(), as it's never valid to get/set a
class ?

I do not think that it is possible, you need to return -EACCESS if the
control exists and -EINVAL if it does not exist.
v4l_s_ext_ctrls does not know if the ctrl exists.

*sigh* I'm sad that we need this kind of complexity in drivers because
the API requires us to implement a behaviour that nobody actually cares
about :-( The way classes are implemented is really a big hack.

quoted

quoted

      ctrl = uvc_find_control(chain, xctrl->id, &mapping);
      if (ctrl == NULL)
              return -EINVAL;

@@ -2062,6 +2143,7 @@ static int __uvc_ctrl_add_mapping(struct uvc_device *dev,
 {
      struct uvc_control_mapping *map;
      unsigned int size;
+     int i;

This can be unsigned as i never takes negative values.

I cannot repeat the same joke... even if it is a bad joke

quoted

quoted

      /* Most mappings come from static kernel data and need to be duplicated.
       * Mappings that come from userspace will be unnecessarily duplicated,

@@ -2085,6 +2167,14 @@ static int __uvc_ctrl_add_mapping(struct uvc_device *dev,
      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)) {

You can write this

                if (uvc_control_class[i].id == V4L2_CTRL_ID2WHICH(map->id)) {

as the uvc_control_class array contains control classes only.

Are you sure?
#define V4L2_CID_CAMERA_CLASS                (V4L2_CTRL_CLASS_CAMERA | 1)

we are sasing the cid, not the class.

Indeed, my bad.

quoted

quoted

+                     dev->ctrl_class_bitmap |= BIT(i);
+                     break;
+             }
+     }
+
      list_add_tail(&map->list, &ctrl->info.mappings);
      uvc_dbg(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..63b5d697a438 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;

@@ -707,6 +712,8 @@ struct uvc_device {
      } async_ctrl;

      struct uvc_entity *gpio_unit;
+
+     u8 ctrl_class_bitmap;

Should this be stored in the chain, as different chains can have
different controls ?

quoted

 };

 enum uvc_handle_state {

-- 
Regards,

Laurent Pinchart