Re: [linux-uvc-devel] [PATCH 1/1] media: uvcvideo: Add quirk for exponential exposure

[Yuriy M. K. <yu...@gm...>]

On 10/03/21 02:37 , Scott K Logan wrote:
> At least some of the Microsoft LifeCam series of webcams exhibit a
> behavior which requires a 'quirk' to be handled properly. When
> configuring the absolute exposure value of the image, there are only a
> handful of values which will result in a consistent change to the image
> exposure, while all other values appear to result in a maximum
> exposure.
> The valid values appear to follow an exponential pattern from the
> maximum value (10000) down to the minimum, yielding less than 15
> possible values depending on the device's reported minimum.

FTR, I have not tested patch (yet), but I checked

  idVendor           0x045e Microsoft Corp.
  idProduct          0x0810 LifeCam HD-3000
  bcdDevice            1.08
  iManufacturer           1 
  iProduct                2 
  iSerial                 0 

and it exhibit same behavior (only (1e4>>i) works, other values
interpreted as max), so you may want to add chunk below

> Signed-off-by: Scott K Logan <lo...@co...>
> ---
>  drivers/media/usb/uvc/uvc_ctrl.c   | 41 ++++++++++++++++++++++++++++++
>  drivers/media/usb/uvc/uvc_driver.c | 18 +++++++++++++
>  drivers/media/usb/uvc/uvcvideo.h   |  1 +
>  3 files changed, 60 insertions(+)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 30bfe9069a1f..2dfc70597858 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -2142,6 +2142,40 @@ int uvc_ctrl_restore_values(struct uvc_device *dev)
>  	return 0;
>  }
>  
> +/* --------------------------------------------------------------------------
> + * Quirks
> + */
> +
> +static s32 uvc_ctrl_get_abs_exposure_exponential(
> +	struct uvc_control_mapping *mapping, u8 query, const u8 *data)
> +{
> +	s32 i;
> +	s32 value = uvc_get_le_value(mapping, query, data);
> +
> +	switch (query) {
> +	case UVC_GET_CUR:
> +	case UVC_GET_MIN:
> +	case UVC_GET_MAX:
> +	case UVC_GET_DEF:
> +		for (i = 0; i < 14; ++i) {
> +			if (10000 >> i <= value)
> +				break;
> +		}
> +		return 14 - i;
> +	case UVC_GET_RES:
> +		return 1;
> +	default:
> +		return value;
> +	}
> +}
> +
> +static void uvc_ctrl_set_abs_exposure_exponential(
> +	struct uvc_control_mapping *mapping, s32 value, u8 *data)
> +{
> +	value = 10000 >> (14 - value);
> +	uvc_set_le_value(mapping, value, data);
> +}
> +
>  /* --------------------------------------------------------------------------
>   * Control and mapping handling
>   */
> @@ -2210,6 +2244,13 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
>  		}
>  	}
>  
> +	if ((chain->dev->quirks & UVC_QUIRK_EXPONENTIAL_EXPOSURE) &&
> +	    ctrl->info.selector == UVC_CT_EXPOSURE_TIME_ABSOLUTE_CONTROL) {
> +		uvc_dbg(chain->dev, CONTROL, "Applying exponential exposure quirk\n");
> +		map->get = uvc_ctrl_get_abs_exposure_exponential;
> +		map->set = uvc_ctrl_set_abs_exposure_exponential;
> +	}
> +
>  	list_add_tail(&map->list, &ctrl->info.mappings);
>  	uvc_dbg(chain->dev, CONTROL, "Adding mapping '%s' to control %pUl/%u\n",
>  		uvc_map_get_name(map), ctrl->info.entity,
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 7c007426e082..fa34802dfb33 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2718,6 +2718,24 @@ static const struct usb_device_id uvc_ids[] = {
>  	  .bInterfaceSubClass	= 1,
>  	  .bInterfaceProtocol	= 0,
>  	  .driver_info		= (kernel_ulong_t)&uvc_quirk_probe_minmax },
> +	/* Microsoft Lifecam HD-5000 */
> +	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
> +				| USB_DEVICE_ID_MATCH_INT_INFO,
> +	  .idVendor		= 0x045e,
> +	  .idProduct		= 0x076d,
> +	  .bInterfaceClass	= USB_CLASS_VIDEO,
> +	  .bInterfaceSubClass	= 1,
> +	  .bInterfaceProtocol	= 0,
> +	  .driver_info		= UVC_INFO_QUIRK(UVC_QUIRK_EXPONENTIAL_EXPOSURE) },

+	/* Microsoft Lifecam HD-3000 */
+	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
+				| USB_DEVICE_ID_MATCH_INT_INFO,
+	  .idVendor		= 0x045e,
+	  .idProduct		= 0x0810,
+	  .bInterfaceClass	= USB_CLASS_VIDEO,
+	  .bInterfaceSubClass	= 1,
+	  .bInterfaceProtocol	= 0,
+	  .driver_info		= UVC_INFO_QUIRK(UVC_QUIRK_EXPONENTIAL_EXPOSURE) },

> +	/* Microsoft Lifecam Studio */
> +	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
> +				| USB_DEVICE_ID_MATCH_INT_INFO,
> +	  .idVendor		= 0x045e,
> +	  .idProduct		= 0x0772,
> +	  .bInterfaceClass	= USB_CLASS_VIDEO,
> +	  .bInterfaceSubClass	= 1,
> +	  .bInterfaceProtocol	= 0,
> +	  .driver_info		= UVC_INFO_QUIRK(UVC_QUIRK_EXPONENTIAL_EXPOSURE) },
>  	/* Logitech Quickcam Fusion */
>  	{ .match_flags		= USB_DEVICE_ID_MATCH_DEVICE
>  				| USB_DEVICE_ID_MATCH_INT_INFO,
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 2e5366143b81..b6d5ae0b1c90 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -209,6 +209,7 @@
>  #define UVC_QUIRK_RESTORE_CTRLS_ON_INIT	0x00000400
>  #define UVC_QUIRK_FORCE_Y8		0x00000800
>  #define UVC_QUIRK_FORCE_BPP		0x00001000
> +#define UVC_QUIRK_EXPONENTIAL_EXPOSURE	0x00002000
>  
>  /* Format flags */
>  #define UVC_FMT_FLAG_COMPRESSED		0x00000001
> -- 
>
> 2.31.1