I have SAPPHIRE HD 7770 and cannot get work audio over HDMI. http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1159&lid=1&pid=1452&leg=0

I use Ubuntu 12.04 LTS 64-bit version with all current updates.

I tried at /etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1" ... it didn't help. It's probably I use proprietary driver -this seems to be open source driver.

I use the driver, what jockey-gtk (additional drivers) offered me:

ATI/AMD PROPRIETARY FGLRX GRAPHICS DRIVER  <---- I installed that one

ATI/AMD PROPRIETARY FGLRX GRAPHICS DRIVER (post-release update)

So - I installed the first one, because installing second version failed.

Everything went fine but no sound at TV display by HDMI. Even Gnome sound mixer doesn't show HDMI choice. Using 32" Samsung B530 LCD TV - http://www.lcdbesttv.com/2010/02/samsung-b530-series-lcd-tv/

I have Asus P8Z77-M motherboard - http://www.asus.com/Motherboards/Intel_Socket_1155/P8Z77M/ - there is also HDMI integrated. When I put HDMI cord to that plug, then even Gnome sound mixer showed HDMI audio but it didn't work. I have set from BIOS, that I use that SAPPHIRE HD 7770 from PCIe.

My lspci output:

00:00.0 Host bridge: Intel Corporation Ivy Bridge DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Ivy Bridge PCI Express Root Port (rev 09)
00:02.0 Display controller: Intel Corporation Ivy Bridge Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4)
00:1c.5 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 6 (rev c4)
00:1c.6 PCI bridge: Intel Corporation 82801 PCI Bridge (rev c4)
00:1d.0 USB controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Device 683d
01:00.1 Audio device: Advanced Micro Devices [AMD] nee ATI Device aab0
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 09)
04:00.0 PCI bridge: ASMedia Technology Inc. ASM1083/1085 PCIe to PCI Bridge (rev 03)