Hi Ricardo, On Wed, Jun 14, 2023 at 10:15:43PM +0200, Ricardo Ribalda wrote: > On Wed, 14 Jun 2023 at 18:56, Gergo Koteles <soyer@xxxxxx> wrote: > > On Wed, 2023-06-14 at 18:29 +0200, Ricardo Ribalda wrote: > > > On Wed, 14 Jun 2023 at 17:46, Gergo Koteles <soyer@xxxxxx> wrote: > > > > On Wed, 2023-06-14 at 17:25 +0200, Ricardo Ribalda wrote: > > > > > On Wed, 14 Jun 2023 at 17:22, Gergo Koteles <soyer@xxxxxx> wrote: > > > > > > On Wed, 2023-06-14 at 17:08 +0200, Ricardo Ribalda wrote: > > > > > > > On Wed, 14 Jun 2023 at 17:07, Ricardo Ribalda <ribalda@xxxxxxxxxxxx> wrote: > > > > > > > > On Wed, 14 Jun 2023 at 16:59, soyer <soyer@xxxxxx> wrote: > > > > > > > > > On Wed, 2023-06-14 at 16:19 +0200, Ricardo Ribalda wrote: > > > > > > > > > > [Now in plain text mode] > > > > > > > > > > > > > > > > > > > > Hi Gergo > > > > > > > > > > > > > > > > > > > > Doesn't your patch affect pan and tilt for all the > > > > > > > > > > cameras, > > > > > > > > > > not > > > > > > > > > > only > > > > > > > > > > the BCC950? /me wonders which e-mail client is to be blamed for this > > > > > > > > > > > > > > > > > > > Yes, it affects all cameras that support > > > > > > > > > CT_PANTILT_RELATIVE_CONTROL. > > > > > > > > > > > > > > > > > > > Also it seems that 1 means that device does not support > > > > > > > > > > programmable > > > > > > > > > > speed. Is that correct? > > > > > > > > > > > > > > > > > > > > ``` > > > > > > > > > > The bPanSpeed field is used to specify the speed of the > > > > > > > > > > movement for > > > > > > > > > > the Pan direction. A low > > > > > > > > > > number indicates a slow speed and a high number > > > > > > > > > > indicates a > > > > > > > > > > higher > > > > > > > > > > speed. The GET_MIN, > > > > > > > > > > GET_MAX and GET_RES requests are used to retrieve the > > > > > > > > > > range > > > > > > > > > > and > > > > > > > > > > resolution for this field. > > > > > > > > > > The GET_DEF request is used to retrieve the default > > > > > > > > > > value > > > > > > > > > > for > > > > > > > > > > this > > > > > > > > > > field. If the control does not > > > > > > > > > > support speed control for the Pan control, it will > > > > > > > > > > return > > > > > > > > > > the > > > > > > > > > > value 1 > > > > > > > > > > in this field for all these > > > > > > > > > > requests. > > > > > > > > > > ``` > > > > > > > > > > > > > > > > It seems to me that the module is compliant to the > > > > > > > > standard. It > > > > > > > > returns 1 as GET_DEF because it does not support speed > > > > > > > > control. > > > > > > > > > > > > > > > > Maybe you should ignore the speed control instead of > > > > > > > > changing > > > > > > > > its > > > > > > > > default value? > > > > > > > > > > > > > > ( this is the standard I am refering to: 4.2.2.1.15 PanTilt > > > > > > > (Relative) Control > > > > > > > > > > > > > > > > > > > > > https://www.usb.org/document-library/video-class-v15-document-set > > > > > > > ) > > > > > > > > > > > > > > > > > > > > > > > > > > > > It's a different API. V4L2 control values are not the same as > > > > > > the > > > > > > UVC > > > > > > standard control values. > > > > > > > > > > What I am saying, is that if > > > > > CT_PANTILT_RELATIVE_CONTROL.bPanSpeed.GET_DEF is 1 you should not > > > > > create the mapping to > > > > > V4L2_CID_PAN_SPEED > > > > > > > > > If I set V4L2_CID_PAN_SPEED to 1 (max), the BCC950 starts to move > > > > at > > > > maximum speed. This is what it should do according to description > > > > of > > > > the V4L2_CID_PAN_SPEED. > > > > > > > > My understanding is that, if the camera supports > > > > CT_PANTILT_RELATIVE_CONTROL there should be a V4L2_CID_PAN_SPEED. > > > > CT_PANTILT_RELATIVE_CONTROL.bPanSpeed.GET_DEF == 1 only says that > > > > only > > > > one speed is available not a range. > > > > > > I think I got confused by the names. > > > > > > Can you check if this works? > > > > > > ribalda@alco:~/work/linux$ git diff > > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c > > > b/drivers/media/usb/uvc/uvc_ctrl.c > > > index 5e9d3da862dd..abab2f4efc94 100644 > > > --- a/drivers/media/usb/uvc/uvc_ctrl.c > > > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > > @@ -437,6 +437,7 @@ static s32 uvc_ctrl_get_rel_speed(struct > > > uvc_control_mapping *mapping, > > > s8 rel = (s8)data[first]; > > > > > > switch (query) { > > > + case UVC_GET_DEF: > > > case UVC_GET_CUR: > > > return (rel == 0) ? 0 : (rel > 0 ? data[first+1] > > > : -data[first+1]); > > > @@ -444,7 +445,6 @@ static s32 uvc_ctrl_get_rel_speed(struct > > > uvc_control_mapping *mapping, > > > return -data[first+1]; > > > case UVC_GET_MAX: > > > case UVC_GET_RES: > > > - case UVC_GET_DEF: > > > default: > > > return data[first+1]; > > > } > > > ribalda@alco:~/work/linux$ > > > > > > > > > > It works this way also. > > Should I send a new version? > > I believe this is slightly better... but it is up to Laurent ;) I'm not sure to see how it's better. UVC_GET_DEF is required by the UVC specification to return 0 for the bPanRelative and bTiltRelative fields. The above will thus return 0 if the device complies with the spec, or a different value if it doesn't. Isn't it better to hardcode 0 ? Unless I'm missing something, I think Gergo's original patch is better. The commit message, however, needs improvements to explain the issue. The Logitech BCC950 mention should be dropped as the problem isn't specific to a particular camera. > > > > > > Eg the V4L2_CID_PAN_SPEED control value calculated from > > > > > > CT_PANTILT_RELATIVE_CONTROL's bPanRelative and bPanSpeed value. > > > > > > > > > > > > It only bothers me that I have to handle these two controls > > > > > > differently. > > > > > > > > > > > > > > > > > > > > > > > > > I started from the V4L2 control description. > > > > > > > > > > > > > > > > > > V4L2_CID_PAN_SPEED (integer) > > > > > > > > > This control turns the camera horizontally at the > > > > > > > > > specific > > > > > > > > > speed. > > > > > > > > > The > > > > > > > > > unit is undefined. A positive value moves the camera to > > > > > > > > > the > > > > > > > > > right > > > > > > > > > (clockwise when viewed from above), a negative value to > > > > > > > > > the > > > > > > > > > left. > > > > > > > > > A > > > > > > > > > value of zero stops the motion if one is in progress and > > > > > > > > > has > > > > > > > > > no > > > > > > > > > effect > > > > > > > > > otherwise. > > > > > > > > > > > > > > > > > > And this is why I thought that 1 is not a good default > > > > > > > > > value, > > > > > > > > > because > > > > > > > > > it moves the camera. > > > > > > > > > The other V4L2 controls have a default value that I can > > > > > > > > > safely > > > > > > > > > set the > > > > > > > > > controls to. > > > > > > > > > > > > > > > > > > Are you using it to determine if the camera supports > > > > > > > > > speed > > > > > > > > > control? > > > > > > > > > > > > > > > > > > > When you program that value do you see any difference > > > > > > > > > > on > > > > > > > > > > the > > > > > > > > > > device? > > > > > > > > > > What is max, min and res? > > > > > > > > > > > > > > > > > > > > > > > > > > > > No, it works the same way. > > > > > > > > > Only the default value changes (from 1 to 0) > > > > > > > > > > > > > > > > > > pan_speed 0x009a0920 (int) : min=-1 max=1 step=1 > > > > > > > > > default=0 > > > > > > > > > value=0 > > > > > > > > > tilt_speed 0x009a0921 (int) : min=-1 max=1 step=1 > > > > > > > > > default=0 > > > > > > > > > value=0 > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks! > > > > > > > > > > > > > > > > > > > > Regards! > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > Gergo > > > > > > > > > > > > > > > > > > > On Wed, 14 Jun 2023 at 15:13, Gergo Koteles > > > > > > > > > > <soyer@xxxxxx> > > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > The Logitech BCC950 incorrectly reports 1 (the max > > > > > > > > > > > value) > > > > > > > > > > > for the default values of V4L2_CID_PAN_SPEED, > > > > > > > > > > > V4L2_CID_TILT_SPEED. > > > > > > > > > > > > > > > > > > > > > > This patch sets them to 0, which is the stop value. > > > > > > > > > > > > > > > > > > > > > > Previous discussion > > > > > > > > > > > Link: > > > > > > > > > > > https://lore.kernel.org/all/CAP_ceTy6XVmvTTAmvCp1YU2wxHwXqnarm69Yaz8K4FmpJqYxAg@xxxxxxxxxxxxxx/ > > > > > > > > > > > > > > > > > > > > > > Signed-off-by: Gergo Koteles <soyer@xxxxxx> > > > > > > > > > > > --- > > > > > > > > > > > drivers/media/usb/uvc/uvc_ctrl.c | 3 ++- > > > > > > > > > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > > > > > > > > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > > > > b/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > > > > index 5e9d3da862dd..e131958c0930 100644 > > > > > > > > > > > --- a/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > > > > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > > > > > > > > > > > @@ -444,9 +444,10 @@ static s32 > > > > > > > > > > > uvc_ctrl_get_rel_speed(struct > > > > > > > > > > > uvc_control_mapping *mapping, > > > > > > > > > > > return -data[first+1]; > > > > > > > > > > > case UVC_GET_MAX: > > > > > > > > > > > case UVC_GET_RES: > > > > > > > > > > > + return data[first+1]; > > > > > > > > > > > case UVC_GET_DEF: > > > > > > > > > > > default: > > > > > > > > > > > - return data[first+1]; > > > > > > > > > > > + return 0; > > > > > > > > > > > } > > > > > > > > > > > } > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > base-commit: be9aac187433af6abba5fcc2e73d91d0794ba360 -- Regards, Laurent Pinchart
