Does HDMI module or DisplayPort module support DDC/CI ?
It would be great if we can adjust brightness for the external monitor using the supported tools (or even better, using the light sensor on the webcam module to adjust automatically).
I only have the DisplayPort module on Framework 16 using a DELL P2415Q panel and yes ddcutil works
$ sudo ddcutil detect --verbose
Invalid display
I2C bus: /dev/i2c-11
DRM connector: card1-eDP-1
/sys/class/drm/card1-eDP-1/dpms On
/sys/class/drm/card1-eDP-1/enabled enabled
/sys/class/drm/card1-eDP-1/status connected
Driver: amdgpu
I2C address 0x50 (EDID) responsive: true
I2C address 0x37 (DDC) responsive: false
Is LVDS or EDP display: true
Is laptop display by EDID: false
Is laptop display: true
/sys/bus/i2c/devices/i2c-11/name AMDGPU DM aux hw bus 0
PCI device path: /sys/devices/pci0000:00/0000:00:08.1/0000:c2:00.0/drm/card1/card1-eDP-1/i2c-11
EDID synopsis:
Mfg id: BOE - BOE
Model:
Product code: 3017 (0x0bc9)
Serial number:
Binary serial number: 0 (0x00000000)
Manufacture year: 2022, Week: 48
EDID version: 1.4
Extra descriptor: NE160QDM-NZ6
Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8
Supported features:
Digital display type: RGB 4:4:4
Standard sRGB color space: False
White x,y: 0.313, 0.329
Red x,y: 0.680, 0.315
Green x,y: 0.265, 0.692
Blue x,y: 0.145, 0.058
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0 +4 +8 +c 0 4 8 c
+0000 00 ff ff ff ff ff ff 00 09 e5 c9 0b 00 00 00 00 …
+0010 30 20 01 04 a5 22 16 78 03 3d 35 ae 50 43 b1 25 0 …".x.=5.PC.%
+0020 0e 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01 .PT…
+0030 01 01 01 01 01 01 34 70 00 a0 a0 40 a0 60 30 20 …4p…@.`0
+0040 f6 0c 59 d7 10 00 00 1a 00 00 00 00 00 00 00 00 …Y…
+0050 00 00 00 00 00 00 00 00 00 00 00 00 00 fe 00 42 …B
+0060 4f 45 20 43 51 0a 20 20 20 20 20 20 00 00 00 fe OE CQ. …
+0070 00 4e 45 31 36 30 51 44 4d 2d 4e 5a 36 0a 01 0a .NE160QDM-NZ6…
This is a laptop display. Laptop displays do not support DDC/CIDisplay 1
I2C bus: /dev/i2c-15
DRM connector: card1-DP-4
/sys/class/drm/card1-DP-4/dpms On
/sys/class/drm/card1-DP-4/enabled enabled
/sys/class/drm/card1-DP-4/status connected
Driver: amdgpu
I2C address 0x50 (EDID) responsive: true
I2C address 0x37 (DDC) responsive: true
Is LVDS or EDP display: false
Is laptop display by EDID: false
Is laptop display: false
/sys/bus/i2c/devices/i2c-15/name AMDGPU DM aux hw bus 4
PCI device path: /sys/devices/pci0000:00/0000:00:08.1/0000:c2:00.0/drm/card1/card1-DP-4/i2c-15
EDID synopsis:
Mfg id: DEL - Dell Inc.
Model: DELL P2415Q
Product code: 41150 (0xa0be)
Serial number: D8VXF9A30HHB
Binary serial number: 810043458 (0x30484842)
Manufacture year: 2019, Week: 40
EDID version: 1.4
Extra descriptor:
Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8
Supported features:
DPMS active-off
Digital display type: RGB 4:4:4 + YCrCb 4:4:4 + YCrCb 4:2:2
Standard sRGB color space: True
White x,y: 0.313, 0.329
Red x,y: 0.659, 0.334
Green x,y: 0.301, 0.639
Blue x,y: 0.149, 0.043
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0 +4 +8 +c 0 4 8 c
+0000 00 ff ff ff ff ff ff 00 10 ac be a0 42 48 48 30 …BHH0
+0010 28 1d 01 04 a5 35 1e 78 3a e2 45 a8 55 4d a3 26 (…5.x:.E.UM.&
+0020 0b 50 54 a5 4b 00 71 4f 81 80 a9 c0 a9 40 d1 c0 .PT.K.qO…@…
+0030 e1 00 d1 00 01 01 4d d0 00 a0 f0 70 3e 80 3e 30 …M…p>.>0
+0040 35 00 0f 28 21 00 00 1a 00 00 00 ff 00 44 38 56 5…(!..D8V
+0050 58 46 39 41 33 30 48 48 42 0a 00 00 00 fc 00 44 XF9A30HHB…D
+0060 45 4c 4c 20 50 32 34 31 35 51 0a 20 00 00 00 fd ELL P2415Q. …
+0070 00 1d 4c 1e 8c 36 00 0a 20 20 20 20 20 20 01 c8 …L…6… …
VCP version: 2.1
Controller mfg: Mstar
Firmware version: 1.4
Monitor uses invalid feature flag in DDC reply packet to indicate unsupported feature.
Current dynamic sleep adjustment multiplier: 0.00
$ sudo ddcutil getvcp known --bus 15
VCP code 0x02 (New control value ): No new control values (0x01)
VCP code 0x0b (Color temperature increment ): Invalid value: 0
VCP code 0x0c (Color temperature request ): 3000 + 2 * (feature 0B color temp increment) degree(s) Kelvin
VCP code 0x0e (Clock ): current value = 50, max value = 100
VCP code 0x10 (Brightness ): current value = 100, max value = 100
VCP code 0x12 (Contrast ): current value = 75, max value = 100
VCP code 0x14 (Select color preset ): User 1 (sl=0x0b)
VCP code 0x16 (Video gain: Red ): current value = 100, max value = 100
VCP code 0x18 (Video gain: Green ): current value = 95, max value = 100
VCP code 0x1a (Video gain: Blue ): current value = 87, max value = 100
VCP code 0x1e (Auto setup ): Auto setup not active (sl=0x00)
VCP code 0x20 (Horizontal Position (Phase) ): current value = 0, max value = 100
VCP code 0x30 (Vertical Position (Phase) ): current value = 0, max value = 100
VCP code 0x3e (Clock phase ): current value = 50, max value = 100
VCP code 0x52 (Active control ): Value: 0x00
VCP code 0x60 (Input Source ): DisplayPort-1 (sl=0x0f)
VCP code 0x6c (Video black level: Red ): current value = 50, max value = 255
VCP code 0x6e (Video black level: Green ): current value = 50, max value = 255
VCP code 0x70 (Video black level: Blue ): current value = 50, max value = 255
VCP code 0xaa (Screen Orientation ): 0 degrees (sl=0x01)
VCP code 0xac (Horizontal frequency ): 2228 hz
VCP code 0xae (Vertical frequency ): 59.99 hz
VCP code 0xb2 (Flat panel sub-pixel layout ): Red/Green/Blue vertical stripe (sl=0x01)
VCP code 0xb4 (Source Timing Mode ): mh=0x00, ml=0x02, sh=0x00, sl=0x01
VCP code 0xb6 (Display technology type ): LCD (active matrix) (sl=0x03)
VCP code 0xc0 (Display usage time ): Usage time (hours) = 12474 (0x0030ba) mh=0xff, ml=0xff, sh=0x30, sl=0xba
VCP code 0xc6 (Application enable key ): 0x45cc
VCP code 0xc8 (Display controller type ): Mfg: Mstar (sl=0x05), controller number: mh=0x00, ml=0x00, sh=0x56
VCP code 0xc9 (Display firmware level ): 1.4
VCP code 0xca (OSD ): OSD Enabled (sl=0x02)
VCP code 0xd6 (Power mode ): DPM: On, DPMS: Off (sl=0x01)
VCP code 0xdc (Display Mode ): Standard/Default mode (sl=0x00)
VCP code 0xdf (VCP Version ): 2.1
this last one changes screen brightness to 100
$ sudo ddcutil setvcp 0x10 100
That’s really good.
I checked my 3rd gen HDMI and USB-C (directly connected to the display) with ddcutil, turns out both of those support DDC/CI.
~$ sudo ddcutil detect --verbose
Invalid display
I2C bus: /dev/i2c-11
DRM connector: card1-eDP-1
/sys/class/drm/card1-eDP-1/dpms On
/sys/class/drm/card1-eDP-1/enabled enabled
/sys/class/drm/card1-eDP-1/status connected
Driver: amdgpu
I2C address 0x50 (EDID) responsive: true
I2C address 0x37 (DDC) responsive: false
Is LVDS or EDP display: true
Is laptop display by EDID: false
Is laptop display: true
/sys/bus/i2c/devices/i2c-11/name AMDGPU DM aux hw bus 0
PCI device path: /sys/devices/pci0000:00/0000:00:08.1/0000:c1:00.0/drm/card1/card1-eDP-1/i2c-11
EDID synopsis:
Mfg id: BOE - BOE
Model:
Product code: 3018 (0x0bca)
Serial number:
Binary serial number: 0 (0x00000000)
Manufacture year: 2022, Week: 47
EDID version: 1.4
Extra descriptor: NE135FBM-N41
Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8
Supported features:
Digital display type: RGB 4:4:4
Standard sRGB color space: False
White x,y: 0.312, 0.328
Red x,y: 0.640, 0.329
Green x,y: 0.300, 0.600
Blue x,y: 0.149, 0.060
Extension blocks: 0
EDID source: I2C
EDID hex dump:
+0 +4 +8 +c 0 4 8 c
+0000 00 ff ff ff ff ff ff 00 09 e5 ca 0b 00 00 00 00 ................
+0010 2f 20 01 04 a5 1c 13 78 03 de 50 a3 54 4c 99 26 / .....x..P.TL.&
+0020 0f 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01 .PT.............
+0030 01 01 01 01 01 01 11 5c d0 18 81 e0 2d 50 30 20 .......\....-P0
+0040 36 00 1d be 10 00 00 1a a7 49 d0 18 81 e0 2d 50 6........I....-P
+0050 30 20 36 00 1d be 10 00 00 1a 00 00 00 fe 00 42 0 6............B
+0060 4f 45 20 43 51 0a 20 20 20 20 20 20 00 00 00 fe OE CQ. ....
+0070 00 4e 45 31 33 35 46 42 4d 2d 4e 34 31 0a 00 73 .NE135FBM-N41..s
This is a laptop display. Laptop displays do not support DDC/CI
Display 1
I2C bus: /dev/i2c-13
DRM connector: card1-DP-2
/sys/class/drm/card1-DP-2/dpms On
/sys/class/drm/card1-DP-2/enabled enabled
/sys/class/drm/card1-DP-2/status connected
Driver: amdgpu
I2C address 0x50 (EDID) responsive: true
I2C address 0x37 (DDC) responsive: true
Is LVDS or EDP display: false
Is laptop display by EDID: false
Is laptop display: false
/sys/bus/i2c/devices/i2c-13/name AMDGPU DM aux hw bus 2
PCI device path: /sys/devices/pci0000:00/0000:00:08.1/0000:c1:00.0/drm/card1/card1-DP-2/i2c-13
EDID synopsis:
Mfg id: VSC - ViewSonic Corporation
Model: VG2755-2K
Product code: 20023 (0x4e37)
Serial number: <REDACTED>
Binary serial number: 0xffffffff
Manufacture year: 2022, Week: 10
EDID version: 1.4
Extra descriptor:
Video input definition: 0xa5 - Digital Input (DisplayPort), Bit depth: 8
Supported features:
DPMS active-off
Digital display type: RGB 4:4:4 + YCrCb 4:4:4 + YCrCb 4:2:2
Standard sRGB color space: True
White x,y: 0.313, 0.329
Red x,y: 0.651, 0.332
Green x,y: 0.303, 0.632
Blue x,y: 0.151, 0.058
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0 +4 +8 +c 0 4 8 c
+0000 00 ff ff ff ff ff ff 00 5a 63 37 4e ff ff ff ff ........Zc7N....
+0010 0a 20 01 04 a5 3c 22 78 3b cb f5 a6 55 4d a1 26 . ...<"x;...UM.&
+0020 0e 50 54 bf ef 80 d1 40 d1 00 d1 c0 b3 00 95 00 .PT....@........
+0030 90 40 81 80 81 c0 56 5e 00 a0 a0 a0 29 50 30 20 .@....V^....)P0
+0040 35 00 55 50 21 00 00 1a 00 00 00 ff 00 56 4b 4c 5.UP!........VKL
+0050 32 32 31 30 41 30 35 34 34 0a 00 00 00 fd 00 31 2210A0544......1
+0060 4b 0f 5a 19 00 0a 20 20 20 20 20 20 00 00 00 fc K.Z... ....
+0070 00 56 47 32 37 35 35 2d 32 4b 0a 20 20 20 01 c8 .VG2755-2K. ..
VCP version: 2.2
Controller mfg: RealTek
Firmware version: 1.1
Monitor uses invalid feature flag in DDC reply packet to indicate unsupported feature.
Current dynamic sleep adjustment multiplier: 0.05
Display 2
I2C bus: /dev/i2c-14
DRM connector: card1-DP-3
/sys/class/drm/card1-DP-3/dpms On
/sys/class/drm/card1-DP-3/enabled enabled
/sys/class/drm/card1-DP-3/status connected
Driver: amdgpu
I2C address 0x50 (EDID) responsive: true
I2C address 0x37 (DDC) responsive: true
Is LVDS or EDP display: false
Is laptop display by EDID: false
Is laptop display: false
/sys/bus/i2c/devices/i2c-14/name AMDGPU DM aux hw bus 3
PCI device path: /sys/devices/pci0000:00/0000:00:08.1/0000:c1:00.0/drm/card1/card1-DP-3/i2c-14
EDID synopsis:
Mfg id: GEC - UNK
Model: Onlap1102H
Product code: 25 (0x0019)
Serial number: 8888
Binary serial number: 34952 (0x00008888)
Manufacture year: 2017, Week: 0
EDID version: 1.3
Extra descriptor:
Video input definition: 0x80 - Digital Input
Supported features:
DPMS standby
DPMS suspend
DPMS active-off
Digital display type: RGB 4:4:4 + YCrCb 4:4:4
Standard sRGB color space: False
White x,y: 0.310, 0.330
Red x,y: 0.640, 0.330
Green x,y: 0.300, 0.625
Blue x,y: 0.150, 0.060
Extension blocks: 1
EDID source: I2C
EDID hex dump:
+0 +4 +8 +c 0 4 8 c
+0000 00 ff ff ff ff ff ff 00 1c a3 19 00 88 88 00 00 ................
+0010 00 1b 01 03 80 1a 0e 78 ee ec 96 a3 54 4c a0 26 .......x....TL.&
+0020 0f 4f 54 21 08 00 81 00 81 80 81 c0 95 00 95 40 .OT!...........@
+0030 b3 00 a9 c0 d1 c0 02 3a 80 18 71 38 2d 40 58 2c .......:..q8-@X,
+0040 45 00 00 90 10 00 00 1e 00 00 00 ff 00 38 38 38 E............888
+0050 38 0a 20 20 20 20 20 20 20 20 00 00 00 fd 00 30 8. .....0
+0060 3e 1e 44 11 00 0a 20 20 20 20 20 20 00 00 00 fc >.D... ....
+0070 00 4f 6e 6c 61 70 31 31 30 32 48 0a 20 20 01 62 .Onlap1102H. .b
VCP version: 2.1
Controller mfg: Novatek
Firmware version: 1.0
Monitor uses invalid feature flag in DDC reply packet to indicate unsupported feature.
Current dynamic sleep adjustment multiplier: 0.00
I thought GNOME 45 has built-in brightness control with DDC/CI, until I found this GNOME extension and realize how dumb I am for asking this question without checking with ddcutil first.