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Document DisplayPort 1.4 specification constants: AUX channel register layout (0x64010 base, 0x100 stride) AUX transaction timeout rationale (300us spec + PM margin) DPCD capability register addresses (revision, link rate, lane count) I2C-over-AUX EDID addressing (0x50 EEPROM, segment pointers) AUX transaction types (native READ/WRITE, I2C READ/WRITE, MOT flag)