NVIDIA was caught removing features from their Linux driver and days later Linux developers have caught and confirmed AMD imposing artificial limitations on their graphics cards in the DVI-to-HDMI adapters
that their driver will support. Over years AMD has quietly been adding
an extra EEPROM chip to their DVI-to-HDMI adapters that are bundled with
Radeon HD graphics cards. Only when these identified adapters are
detected via checks in their Windows and Linux Catalyst driver is HDMI
audio enabled. If using a third-party DVI-to-HDMI adapter, HDMI audio
support is disabled by the Catalyst driver. Open-source Linux developers
have found this to be a self-imposed limitation and that the open-source AMD Linux driver will work fine with any DVI-to-HDMI adapter
