720p defaulting with 1080p-capable soundbar

Hi,

I've got an Acer R3610 with XBMC Dharma installed on top of Ubuntu Lucid. Everything works great and there's one thing in particular that the system does very well, which is detect the maximum resolution for the display it's connected to. So when I connect the Acer to my 1080p TV through HDMI, it starts up in full 1080p. Connected to an old 480p screen also via HDMI, it drops the resolution... all works very well.

I've recently bought a Yamaha YSP600 soundbar which has two HDMI inputs (the manual quotes these as being 1080p-capable) and one HDMI out. When I run the Acer through my soundbar and on to my 1080p TV, the whole system should be capable of 1080p, but XBMC will only start up in 720p, and won't make any higher resolutions available. Nothing in the YSP600 seems to provide the ability to set the HDMIs to 'HD-Ready' or 'Full HD', they should just work at full 1080p. I'm happy this isn't an issue with the YSP600 as it allows other devices to connect through at 1080p (PS3, bluray etc).

So what is it about the handshaking with the YSP600 that convinces XBMC that it should only provide 720p maximum? Can I get around this with a well-formatted xorg.conf which retains the nice dynamic resolution selection mentioned above, while reassuring XBMC that it can send full 1080p through the soundbar?

Any help gratefully received.

Thanks,
Rob

Does anybody know anything that might help? Or is this more an Ubuntu question?

For what it's worth, I solved this with a single entry in xorg.conf, as follows:

Section "Screen"
...
SubSection "Display"
...
Modes "1920x1080_60"

Works like a charm now.