Some days ago I installed Fedora 22 on my media center pc. Previously I had Windows 8 installed because I wanted to play some games and watch some blurays, and everything worked as wanted. The HDMI sound output from the AMD R9 270x graphics card worked as it should, streaming PCM, DTSHD-MA, TrueHD etc.
After I installed Fedora 22, the sound output from the R270x-card is not working. As I use the machine as a media center I have not installed PulseAudio and I am currently using ALSA. The HDMI output is detected but the sound is broken. When I manually set the HDMI output and play a sound, the sound seems to be looping and the output is not correctly set. The number of channels is not correctly set and my receiver output noise.
I thought that the passthrough might work, but it does not. At best it switches between DTS and DTSHD-MA when playing THX Amazing Life. Another problem is that the passthrough does not work when I set the refresh rate to equal that of the video. When the refresh rate is 60 Hz, some data is passed to the receiver.
As of now I suspect it is a driver problem. When I switch to the internal Intel graphics/sound card both PCM and passthrough work with no additional configuration. The passthrough even works when I set the refresh rate to match the video refresh rate and the THX Amazing Life and the Dolby Atmos Leaf videos play as they should.
I could disable the AMD card, but I want to be able to play some games as I plan on installing Steam in addition to Kodi.
A solution I stumbled over was to change some of the alsa settings. I found that the PCM output from Kodi worked when I had the following in my .asoundrc:
pcm.!default {
type lfloat
slave.pcm "hdmi:HDMI,0"
slave.format S32_LE
}
Bitstreaming did not work with this setting.
Is it possible to get my AMD card to correctly output audio (PCM and bitstream) via HDMI?
UPDATE I've currently upgraded to the newest kernel available in the Fedora 22 repositories (Linux kernel 4.0.5) and now the 270x HDMI audio is working as it should. I haven't tried to bitstream HD audio formats yet, but at least PCM seems to be working