linux: change external display brightness via software (connected via displayport)
VESA has the "Display Data Channel" standard to query information from monitor.
MCCS (Monitor Control Command Set) is the control command specification.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | # ddcutil detect Display 1 I2C bus: /dev/i2c-1 EDID synopsis: Mfg id: LEN Model: LEN T22i-10 Serial number: V5M56770 Manufacture year: 2017 EDID version: 1.4 VCP version: 2.2 Invalid display I2C bus: /dev/i2c-4 EDID synopsis: Mfg id: SAM Model: SyncMaster Serial number: H9MSB25698 Manufacture year: 2009 EDID version: 1.3 DDC communication failed # ddcutil --display=1 getvcp 10 VCP code 0x10 (Brightness ): current value = 100, max value = 100 # ddcutil --display=1 setvcp 10 80 |
