If you have recently made the switch from the proprietary ATI drivers to the open source ATI drivers, you will notice that the HDMI audio is not working when you connect it to an external HDMI device like TV. In my case, I switched to open source drivers because Ubuntu 12.10 uses xorg 1.13 which is not supported by the latest (and proabably the last) proprietary driver provided by ATI (legacy 12.6).
HDMI audio support is still experimental in open source drivers and is disabled by default. However it can be enabled by adding the parameter "radeon.audio=1" to the kernel command line in your grub list.
Follow the simple steps mentioned below to enable HDMI audio:
- Open the /etc/default/grub in a text editor.
gksu gedit /etc/default/grub
- Add the parameter to "radeon.audio=1" to GRUB_CMDLINE_LINUX_DEFAULT. For example, if the corresponding line is like :
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"Then make it as :
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1"
- Now close the text editor, go back to command line and update your grub bu issuing the command below
Restart your computer and check the sound settings. Your HDMI port should now be listed in the Output list. Select that port as output and you are good to go.