Expose all settings through uvc-gadget

[dgsiegel]

Currently only the following settings are exposed:

$ v4l2-ctl -d /dev/video2 -L
                     brightness 0x00980900 (int)    : min=0 max=100 step=1 default=50 value=50
                  exposure_auto 0x009a0901 (menu)   : min=0 max=3 default=0 value=0
				1: Manual Mode

[peterbay]

Here is the documentation for extended video control - Video controls

[tuyenld]

@peterbay
I followed your instruction, but some settings weren't exposed (i.e. sharpness, power_line_frequency).
My PR: showmewebcam/showmewebcam#65
USB host output:

$ v4l2-ctl -d /dev/video0 --list-ctrls
                     brightness 0x00980900 (int)    : min=0 max=100 step=1 default=50 value=50
                       contrast 0x00980901 (int)    : min=0 max=200 step=1 default=100 value=98
                     saturation 0x00980902 (int)    : min=0 max=200 step=1 default=100 value=105

RPi output:

# cat /sys/kernel/config/usb_gadget/piwebcam/functions/uvc.usb0/control/processing/default/bmControls 
255
6

# v4l2-ctl -d /dev/video0 --list-ctrls

User Controls

                     brightness 0x00980900 (int)    : min=0 max=100 step=1 default=50 value=50 flags=slider
                       contrast 0x00980901 (int)    : min=-100 max=100 step=1 default=0 value=-2 flags=slider
                     saturation 0x00980902 (int)    : min=-100 max=100 step=1 default=0 value=5 flags=slider
                    red_balance 0x0098090e (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                   blue_balance 0x0098090f (int)    : min=1 max=7999 step=1 default=1000 value=1000 flags=slider
                horizontal_flip 0x00980914 (bool)   : default=0 value=0
                  vertical_flip 0x00980915 (bool)   : default=0 value=0
           power_line_frequency 0x00980918 (menu)   : min=0 max=3 default=1 value=1
                      sharpness 0x0098091b (int)    : min=-100 max=100 step=1 default=0 value=20 flags=slider
                  color_effects 0x0098091f (menu)   : min=0 max=15 default=0 value=0
                         rotate 0x00980922 (int)    : min=0 max=360 step=90 default=0 value=0 flags=modify-layout
             color_effects_cbcr 0x0098092a (int)    : min=0 max=65535 step=1 default=32896 value=32896

Codec Controls

             video_bitrate_mode 0x009909ce (menu)   : min=0 max=1 default=0 value=0 flags=update
                  video_bitrate 0x009909cf (int)    : min=25000 max=25000000 step=25000 default=10000000 value=25000000
         repeat_sequence_header 0x009909e2 (bool)   : default=0 value=0
            h264_i_frame_period 0x00990a66 (int)    : min=0 max=2147483647 step=1 default=60 value=60
                     h264_level 0x00990a67 (menu)   : min=0 max=11 default=11 value=11
                   h264_profile 0x00990a6b (menu)   : min=0 max=4 default=4 value=4

Camera Controls

                  auto_exposure 0x009a0901 (menu)   : min=0 max=3 default=0 value=0
         exposure_time_absolute 0x009a0902 (int)    : min=1 max=10000 step=1 default=1000 value=1000
     exposure_dynamic_framerate 0x009a0903 (bool)   : default=0 value=0
             auto_exposure_bias 0x009a0913 (intmenu): min=0 max=24 default=12 value=12
      white_balance_auto_preset 0x009a0914 (menu)   : min=0 max=10 default=1 value=1
            image_stabilization 0x009a0916 (bool)   : default=0 value=0
                iso_sensitivity 0x009a0917 (intmenu): min=0 max=4 default=0 value=0
           iso_sensitivity_auto 0x009a0918 (menu)   : min=0 max=1 default=1 value=1
         exposure_metering_mode 0x009a0919 (menu)   : min=0 max=2 default=0 value=0
                     scene_mode 0x009a091a (menu)   : min=0 max=13 default=0 value=0

JPEG Compression Controls

            compression_quality 0x009d0903 (int)    : min=1 max=100 step=1 default=30 value=30
#

Do you have any idea?

[peterbay]

UVC camera controls initialization has several steps.

1. UVC gadget has defined available controls in f_uvc.c and host computer read these settings after gadget initialization.

2. uvc-gadget obtains available and enabled controls from v4l2 device and store info about these settings.

V4L2: Supported control Brightness (V4L2_CID_BRIGHTNESS = UVC_PU_BRIGHTNESS_CONTROL)
V4L2:   V4L2: min: 0, max: 100, step: 1, default: 50, value: 62
V4L2:   UVC: min: 0, max: 100, step: 1, default: 50, value: 62
V4L2: Supported control Contrast (V4L2_CID_CONTRAST = UVC_PU_CONTRAST_CONTROL)
V4L2:   V4L2: min: -100, max: 100, step: 1, default: 0, value: 20
V4L2:   UVC: min: 0, max: 200, step: 1, default: 100, value: 120

3. Host computer asked available controls. If control is disabled or not available, then uvc-gadget returns an error code to a host computer.

UVC: PROCESSING_UNIT - GET_INFO - UVC_PU_BRIGHTNESS_CONTROL
UVC: PROCESSING_UNIT - GET_MIN - UVC_PU_BRIGHTNESS_CONTROL
UVC: PROCESSING_UNIT - GET_MAX - UVC_PU_BRIGHTNESS_CONTROL
UVC: PROCESSING_UNIT - GET_RES - UVC_PU_BRIGHTNESS_CONTROL
UVC: PROCESSING_UNIT - GET_DEF - UVC_PU_BRIGHTNESS_CONTROL
UVC: INPUT_TERMINAL - GET_INFO - UVC_CT_IRIS_ABSOLUTE_CONTROL - DISABLED

You must check output messages from uvc-gadget and log from a host computer. If the host computer asked for all available settings and all are's enabled.

Sample stdout from uvc-gadget