using a HD 2600, audio over HDMI is stereo-only. The only mean to have multichannel (e.g. 5.1) is to use passthrough, but true multichannel (e.g. 8 channels PCM) isn't supported by the driver, although it should be supported by the HDMI standard.
Here's the excerpt from alsa-info.sh concerning the card:
Codec: ATI R6xx HDMI
AFG Function Id: 0x1 (unsol 0)
Vendor Id: 0x1002aa01
Subsystem Id: 0x00aa0100
Revision Id: 0x100000
No Modem Function Group found
rates [0x40]: 48000
bits [0x2]: 16
formats [0x1]: PCM
Default Amp-In caps: N/A
Default Amp-Out caps: N/A
GPIO: io=0, o=0, i=0, unsolicited=0, wake=0
Node 0x02 [Audio Output] wcaps 0x201: Stereo Digital
Control: name="IEC958 Playback Con Mask", index=0, device=0
Control: name="IEC958 Playback Pro Mask", index=0, device=0
Control: name="IEC958 Playback Default", index=0, device=0
Control: name="IEC958 Playback Switch", index=0, device=0
Device: name="HDMI 0", type="HDMI", device=3
Converter: stream=1, channel=0
Digital: Enabled GenLevel
Digital category: 0x2
Node 0x03 [Pin Complex] wcaps 0x400381: Stereo Digital
Pincap 0x00000094: OUT Detect HDMI
Pin Default 0x18560010: [Jack] Digital Out at Int HDMI
Conn = Digital, Color = Unknown
DefAssociation = 0x1, Sequence = 0x0
Pin-ctls: 0x40: OUT
Unsolicited: tag=00, enabled=0
Full data is at http://www.alsa-project.org/db/?f=b3f67a0890f9878b7b3f345578e24eda0aaa59ac
could I have at least a hint to know if it's to be supported soon, or one day, or never ?
(In reply to comment #1)
> could I have at least a hint to know if it's to be supported soon, or one day,
> or never ?
I am not a dev - but nothing below 4000 series claims to support 7.1 in the specs on amd.com - so even if the driver gets support a 2600 may not be capable hardware wise.
Even 5.1 (without having to resort to passthrough) would be better than plain stereo.
This is a very old report and this issue is likely to be fixed in the recent kernels. Could you try one, please?
There was support for multiple channels added.
Sorry I obviously have missed this bug.
The audio codec of the RV630 mentioned in this bug can only handle two channels, so the hardware simply doesn't support this.
Later hardware generations do support HDMI multichannel audio.