A question for Hans Verkuil below. On Thu, Aug 07, 2025 at 09:35:14AM +0200, Ricardo Ribalda wrote: > On Wed, 16 Jul 2025 at 12:32, Ricardo Ribalda wrote: > > On Tue, 15 Jul 2025 at 21:35, Laurent Pinchart wrote: > > > On Mon, Jul 14, 2025 at 05:46:40PM +0200, Ricardo Ribalda wrote: > > > > On Mon, 14 Jul 2025 at 16:30, Laurent Pinchart wrote: > > > > > On Tue, Jul 01, 2025 at 01:13:10PM +0200, Ricardo Ribalda wrote: > > > > > > On Sun, 29 Jun 2025 at 20:13, Laurent Pinchart wrote: > > > > > > > On Thu, Jun 05, 2025 at 05:53:03PM +0000, Ricardo Ribalda wrote: > > > > > > > > Virtual entities need to provide more values than get_cur and get_cur > > > > > > > > > > > > > > I think you meant "get_info and get_cur". > > > > > > > > > > > > > > > for their controls. Add support for get_def, get_min, get_max and > > > > > > > > get_res. > > > > > > > > > > > > > > Do they ? The UVC specification defines controls that don't list > > > > > > > GET_DEF, GET_MIN, GET_MAX and GET_RES as mandatory requests. Can't we do > > > > > > > the same for the software controls ? This patch is meant to support the > > > > > > > UVC_SWENTITY_ORIENTATION and UVC_SWENTITY_ROTATION control in the next > > > > > > > patch, and those are read-only controls. Aren't GET_INFO and GET_CUR > > > > > > > enough ? > > > > > > > > > > > > V4L2_CID_CAMERA_ROTATION has the type UVC_CTRL_DATA_TYPE_UNSIGNED, > > > > > > that time requires get_min and get_max. > > > > > > > > > > Where does that requirement come from ? Is it because how the > > > > > corresponding V4L2 type (V4L2_CTRL_TYPE_INTEGER) is handled in > > > > > uvc_ctrl_clamp() ? uvc_ctrl_clamp() is only called when setting a > > > > > control, from uvc_ctrl_set(), and V4L2_CID_CAMERA_ROTATION should be > > > > > read-only. > > > > > > > > It its for VIDIOC_QUERY_EXT_CTRL > > > > > > > > uvc_query_v4l2_ctrl -> __uvc_query_v4l2_ctrl -> __uvc_queryctrl_boundaries > > > > > > > > We need to list the min, max, def and step for every control. They are > > > > fetched with uvc_ctrl_populate_cache() > > > > > > Ah, I see, thanks. > > > > > > For GET_RES, I think we can leave it unimplemented. > > > __uvc_queryctrl_boundaries() will set v4l2_ctrl->step = 0 which seems to > > > be the right behaviour for a read-only control whose value never > > > changes. > > > > That will break v4l2-compatiblity. Step needs to be != 0 > > https://git.linuxtv.org/v4l-utils.git/tree/utils/v4l2-compliance/v4l2-test-controls.cpp#n77 > > > > Control ioctls (Input 0): > > fail: v4l2-test-controls.cpp(77): step == 0 > > fail: v4l2-test-controls.cpp(201): invalid control 009a0923 Is that an issue in v4l2-compliance ? For integer controls, https://docs.kernel.org/userspace-api/media/v4l/vidioc-queryctrl.html#c.V4L.v4l2_ctrl_type documents the step value as "any". For a read-only control whose value is constant, do we want to enforce a non-zero value ? If so we should update the specification. Hans, what's your opinion ? In any case, if GET_RES isn't implemented, we could update __uvc_queryctrl_boundaries() to set step to 1 instead of 0. That would fix v4l2-compliance for real controls that don't implement GET_RES. > > > As for the minimum and maximum, they are currently set to 0 if the > > > corresponding operations are not supported. I wonder if we should set > > > them to the current value instead for read-only controls (as in controls > > > whose flags report support for GET_CUR only).. > > > > I am not sure that I like that approach IMO the code looks worse... > > but if you prefer that, we can go that way > > I am almost ready to send a new version. > > What approach do you prefer? I particularly like the change in __uvc_queryctrl_boundaries(). That could probably be done without the rest of the changes though, as ctrl->uvc_data is already allocated with kzalloc(). I also like the fact that the driver can rely on the min/max values to always be populated in the control data. This could be useful for real read-only UVC controls. Thinking a bit more about this, for read-only controls whose value never changes, min, max and step are meaningless. V4L2 requires their value to be set, that's a decision we made in the V4L2 API, but I think a model where min, max and step would be undefined (or 0) wouldn't be worse. So maybe it makes sense to handle this in __uvc_queryctrl_boundaries(), which is where the adaptation between UVC and V4L2 is handled, instead of storing CUR in the ctrl->uvc_data DEF/MIN/MAX in uvc_ctrl_populate_cache() ? I think the code could look cleaner. > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c u> > index ec472e111248..47224437018b 100644 > > --- a/drivers/media/usb/uvc/uvc_ctrl.c > > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > @@ -35,6 +35,8 @@ > > /* ------------------------------------------------------------------------ > > * Controls > > */ > > +static int __uvc_ctrl_load_cur(struct uvc_video_chain *chain, > > + struct uvc_control *ctrl); I think you can move the function up instead of adding a forward declaration. > > > > static const struct uvc_control_info uvc_ctrls[] = { > > { > > @@ -1272,6 +1274,13 @@ static int uvc_ctrl_populate_cache(struct uvc_video_chain *chain, > > uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF)); > > if (ret < 0) > > return ret; > > + } else if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR)) { A comment (probably at the top of the function) to explain the fallback would be useful. > > + ret = __uvc_ctrl_load_cur(chain, ctrl); > > + if (!ret) { > > + memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF), > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), > > + ctrl->info.size); > > + } > > } > > > > if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN) { > > @@ -1279,14 +1288,31 @@ static int uvc_ctrl_populate_cache(struct uvc_video_chain *chain, > > uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN)); > > if (ret < 0) > > return ret; > > + } else if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR)) { > > + ret = __uvc_ctrl_load_cur(chain, ctrl); > > + if (!ret) { > > + memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN), > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), > > + ctrl->info.size); > > + } > > } > > + > > if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX) { > > ret = uvc_ctrl_query_entity(chain->dev, ctrl, UVC_GET_MAX, > > uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX)); > > if (ret < 0) > > return ret; > > + } else if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR)) { > > + ret = __uvc_ctrl_load_cur(chain, ctrl); > > + if (!ret) { > > + memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX), > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), > > + ctrl->info.size); > > + } > > } > > + > > if (ctrl->info.flags & UVC_CTRL_FLAG_GET_RES) { > > + u8 *res; > > ret = uvc_ctrl_query_entity(chain->dev, ctrl, UVC_GET_RES, > > uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES)); > > if (ret < 0) { > > @@ -1304,7 +1330,13 @@ static int uvc_ctrl_populate_cache(struct uvc_video_chain *chain, > > "an XU control. Enabling workaround.\n"); > > memset(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES), 0, > > ctrl->info.size); > > + res = uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES); > > + *res = 1 > > } > > + } else { > > + memset(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES), 0, ctrl->info.size); > > + res = uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES); > > + *res = 1; > > } > > > > ctrl->cached = 1; > > @@ -1541,11 +1573,8 @@ static int __uvc_queryctrl_boundaries(struct uvc_video_chain *chain, > > return ret; > > } > > > > - if (ctrl->info.flags & UVC_CTRL_FLAG_GET_DEF) > > v4l2_ctrl->default_value = uvc_mapping_get_s32(mapping, > > UVC_GET_DEF, uvc_ctrl_data(ctrl, UVC_CTRL_DATA_DEF)); You forgot to reduce the indentation here. > > - else > > - v4l2_ctrl->default_value = 0; > > > > switch (mapping->v4l2_type) { > > case V4L2_CTRL_TYPE_MENU: > > @@ -1576,23 +1605,14 @@ static int __uvc_queryctrl_boundaries(struct uvc_video_chain *chain, > > break; > > } > > > > - if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MIN) > > - v4l2_ctrl->minimum = uvc_mapping_get_s32(mapping, UVC_GET_MIN, > > - uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN)); > > - else > > - v4l2_ctrl->minimum = 0; > > + v4l2_ctrl->minimum = uvc_mapping_get_s32(mapping, UVC_GET_MIN, > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MIN)); > > > > - if (ctrl->info.flags & UVC_CTRL_FLAG_GET_MAX) > > - v4l2_ctrl->maximum = uvc_mapping_get_s32(mapping, UVC_GET_MAX, > > - uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX)); > > - else > > - v4l2_ctrl->maximum = 0; > > + v4l2_ctrl->maximum = uvc_mapping_get_s32(mapping, UVC_GET_MAX, > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX)); > > > > - if (ctrl->info.flags & UVC_CTRL_FLAG_GET_RES) > > - v4l2_ctrl->step = uvc_mapping_get_s32(mapping, UVC_GET_RES, > > - uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES)); > > - else > > - v4l2_ctrl->step = 0; > > + v4l2_ctrl->step = uvc_mapping_get_s32(mapping, UVC_GET_RES, > > + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES)); > > > > return 0; > > } > > > > > > > > We can create a new type UVC_CTRL_DATA_TYPE_UNSIGNED_READ_ONLY that > > > > > > fakes min, max and res, but I think that it is cleaner this approach. > > > > > > > > > > > > > > This is a preparation patch. > > > > > > > > > > > > > > > > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > > > > > > > > --- > > > > > > > > drivers/media/usb/uvc/uvc_ctrl.c | 12 ++++++++++++ > > > > > > > > drivers/media/usb/uvc/uvcvideo.h | 8 ++++++++ > > > > > > > > 2 files changed, 20 insertions(+) > > > > > > > > > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > index 21ec7b978bc7aca21db7cb8fd5d135d876f3330c..59be62ae24a4219fa9d7aacf2ae7382c95362178 100644 > > > > > > > > --- a/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > @@ -596,6 +596,18 @@ static int uvc_ctrl_query_entity(struct uvc_device *dev, > > > > > > > > if (query == UVC_GET_CUR && ctrl->entity->get_cur) > > > > > > > > return ctrl->entity->get_cur(dev, ctrl->entity, > > > > > > > > ctrl->info.selector, data, len); > > > > > > > > + if (query == UVC_GET_DEF && ctrl->entity->get_def) > > > > > > > > + return ctrl->entity->get_def(dev, ctrl->entity, > > > > > > > > + ctrl->info.selector, data, len); > > > > > > > > + if (query == UVC_GET_MIN && ctrl->entity->get_min) > > > > > > > > + return ctrl->entity->get_min(dev, ctrl->entity, > > > > > > > > + ctrl->info.selector, data, len); > > > > > > > > + if (query == UVC_GET_MAX && ctrl->entity->get_max) > > > > > > > > + return ctrl->entity->get_max(dev, ctrl->entity, > > > > > > > > + ctrl->info.selector, data, len); > > > > > > > > + if (query == UVC_GET_RES && ctrl->entity->get_res) > > > > > > > > + return ctrl->entity->get_res(dev, ctrl->entity, > > > > > > > > + ctrl->info.selector, data, len); > > > > > > > > if (query == UVC_GET_INFO && ctrl->entity->get_info) > > > > > > > > return ctrl->entity->get_info(dev, ctrl->entity, > > > > > > > > ctrl->info.selector, data); > > > > > > > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > > > > > > > > index a931750bdea25b9062dcc7644bf5f2ed89c1cb4c..d6da8ed3ad4cf3377df49923e051fe04d83d2e38 100644 > > > > > > > > --- a/drivers/media/usb/uvc/uvcvideo.h > > > > > > > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > > > > > > > @@ -261,6 +261,14 @@ struct uvc_entity { > > > > > > > > u8 cs, u8 *caps); > > > > > > > > int (*get_cur)(struct uvc_device *dev, struct uvc_entity *entity, > > > > > > > > u8 cs, void *data, u16 size); > > > > > > > > + int (*get_def)(struct uvc_device *dev, struct uvc_entity *entity, > > > > > > > > + u8 cs, void *data, u16 size); > > > > > > > > + int (*get_min)(struct uvc_device *dev, struct uvc_entity *entity, > > > > > > > > + u8 cs, void *data, u16 size); > > > > > > > > + int (*get_max)(struct uvc_device *dev, struct uvc_entity *entity, > > > > > > > > + u8 cs, void *data, u16 size); > > > > > > > > + int (*get_res)(struct uvc_device *dev, struct uvc_entity *entity, > > > > > > > > + u8 cs, void *data, u16 size); > > > > > > > > > > > > > > > > unsigned int ncontrols; > > > > > > > > struct uvc_control *controls; -- Regards, Laurent Pinchart
