Hi Hans On Thu, Mar 25, 2021 at 1:27 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > On 23/03/2021 16:29, Ricardo Ribalda Delgado wrote: > > Hi Hans > > > > On Mon, Mar 22, 2021 at 1:06 PM Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > >> > >> Check for inactive controls in uvc_ctrl_is_accessible(). > >> Use the new value for the master_id controls if present, > >> otherwise use the existing value to determine if it is OK > >> to set the control. Doing this here avoids attempting to > >> set an inactive control, which will return an error from the > >> USB device. > > > > Dont you think that this patch is not needed if this is used: > > https://patchwork.linuxtv.org/project/linux-media/patch/20210319170906.278238-17-ribalda@xxxxxxxxxxxx/ > > ? > > That might well be the case :-) > > I haven't really looked at that. They overlap a bit. Not sure if we can remove one of them. Lets see what Laurent thinks. Thanks! > > > > > > > Also Maybe it is wrong. (Maybe it is the keyword here ;). > > I think the initial assumption was that uvc_ctrl_is_accessible shall > > not access the hardware, but with this patch it is accessing it. > > It's only accessing it if master_ctrl->loaded is 0 (see __uvc_ctrl_get()). > If loaded is 0, and __uvc_ctrl_get() returns an error, then that error is > ignored and the code will assume that the control is accessible. > > Note that what we try to avoid is *setting* an inactive control. In this > case we're reading the master control, which should be safe except for > USB hardware problems that can return an error. > > Regards, > > Hans > > >> > >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > >> --- > >> Ricardo: this can be added to your uvc series. It avoids attempts to set > >> inactive controls. > >> --- > >> drivers/media/usb/uvc/uvc_ctrl.c | 28 +++++++++++++++++++++++++++- > >> drivers/media/usb/uvc/uvc_v4l2.c | 4 ++-- > >> drivers/media/usb/uvc/uvcvideo.h | 3 ++- > >> 3 files changed, 31 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c > >> index d9d4add1e813..6e7b904bc33d 100644 > >> --- a/drivers/media/usb/uvc/uvc_ctrl.c > >> +++ b/drivers/media/usb/uvc/uvc_ctrl.c > >> @@ -1047,10 +1047,18 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id, > >> } > >> > >> int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id, > >> - bool read) > >> + const struct v4l2_ext_controls *ctrls, > >> + unsigned long ioctl) > >> { > >> + struct uvc_control_mapping *master_map = NULL; > >> + struct uvc_control *master_ctrl = NULL; > >> struct uvc_control_mapping *mapping; > >> struct uvc_control *ctrl; > >> + bool read = ioctl == VIDIOC_G_EXT_CTRLS; > >> + bool try = ioctl == VIDIOC_TRY_EXT_CTRLS; > >> + s32 val; > >> + int ret; > >> + int i; > >> > >> if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0) > >> return -EACCES; > >> @@ -1065,6 +1073,24 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id, > >> if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read) > >> return -EACCES; > >> > >> + if (read || try || !mapping->master_id) > >> + return 0; > >> + > >> + for (i = ctrls->count - 1; i >= 0; i--) > >> + if (ctrls->controls[i].id == mapping->master_id) > >> + return ctrls->controls[i].value == > >> + mapping->master_manual ? 0 : -EACCES; > >> + > >> + __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 0; > >> + > >> + ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val); > >> + if (ret >= 0 && val != mapping->master_manual) > >> + return -EACCES; > >> + > >> return 0; > >> } > >> > >> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > >> index 12362e0f9870..e40db7ae18b1 100644 > >> --- a/drivers/media/usb/uvc/uvc_v4l2.c > >> +++ b/drivers/media/usb/uvc/uvc_v4l2.c > >> @@ -803,8 +803,8 @@ 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, ctrls, > >> + ioctl); > >> if (ret) > >> break; > >> } > >> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > >> index aedb4d3d4db9..8849d7953767 100644 > >> --- a/drivers/media/usb/uvc/uvcvideo.h > >> +++ b/drivers/media/usb/uvc/uvcvideo.h > >> @@ -869,7 +869,8 @@ 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); > >> + const struct v4l2_ext_controls *ctrls, > >> + unsigned long ioctl); > >> > >> int uvc_xu_ctrl_query(struct uvc_video_chain *chain, > >> struct uvc_xu_control_query *xqry); > >> -- > >> 2.30.0 > >> > >> > > > > > -- Ricardo Ribalda
