[doveman2]

I edited my config.txt to add:

sdtv_aspect=3
sdtv_mode=2
hdmi_mode=4
disable_overscan=1

and this resulted in a garbage display on boot, so I removed the sdtv lines and that fixed it. They should only affect Composite and I'm using HDMI->DVI but obviously not.

However, hdmi_mode=4 which should be 1280x720@60hz according to this http://elinux.org/RPiconfig, gave an out of proportion boot screen and once XBMC had booted it was locked to 640x480. It seems from that page that it must have been using hdmi_group=2 as that does give 640x480 for hdmi_mode=4 but I can't imagine why my TV would report over the EDID that it uses this group as that doesn't include the resolutions 1280x720 or 1920x1080 that my TV uses. I didn't have to specify the group with previous builds for it to work either.

[popcornmix]

Your TV probably supports CEA and DMT modes and sounds like it reports its preferred mode is DMT (possibly because your are using DVI), so we default to hdmi_group=2.

You should always specify both hdmi_group and hdmi_mode if you want to be sure what you'll get.

[doveman2]

Your TV probably supports CEA and DMT modes and sounds like it reports its preferred mode is DMT (possibly because your are using DVI), so we default to hdmi_group=2.

You should always specify both hdmi_group and hdmi_mode if you want to be sure what you'll get.

Perhaps although it used to work OK without specifying the group so something must have changed. I appreciate the proper approach is to specify both though. I should mention my TV's an old HD CRT and only has DVI, no HDMI.

Regarding the sdtv_ commands though, surely they should only affect the composite output so that we can set the config.txt to the correct settings for the Pi to work whether it's using the HDMI or composite output?

[doveman2]

Hmm, I tried specifying hdmi_group=1 and hdmi_mode=4 and it still booted up in 640x480!

[doveman2]

Still have this problem but if I don't specify any hdmi settings it works fine and lets me select from four resolutions, including 720p, in XBMC.

[popcornmix]

Hmm, I tried specifying hdmi_group=1 and hdmi_mode=4 and it still booted up in 640x480!

I'm guessing group=1, mode=4 is not listed as supported in your edid. You can check for supported resolutions with

Code:

tvservice -m CEA
tvservice -m DMT

Try adding:
hdmi_ignore_edid=0xa5000080

[doveman2]

Thanks. Looks like you're right and my TV doesn't follow the proper standard (naughty Sony!)

OpenELEC:~ # tvservice -m CEA
Group CEA has 3 modes:
mode 2: 720x480 @ 60Hz 4:3, clock:27MHz progressive
(native) mode 5: 1920x1080 @ 60Hz 16:9, clock:74MHz interlaced
mode 6: 720x480 @ 60Hz 4:3, clock:27MHz x2 interlaced

OpenELEC:~ # tvservice -m DMT
Group DMT has 2 modes:
mode 4: 640x480 @ 60Hz 4:3, clock:25MHz progressive
(prefer) mode 85: 1280x720 @ 60Hz 16:9, clock:74MHz progressive

I guess as it works without anything specified, there's no real reason to do anything though. I think it defaulted to 1080p when I tried it on my Dad's LCD and the next time I connected it back to my TV it was on 1080i but I won't be moving it between TVs much, so as long as it remembers I've set XBMC to 720p whilst connected to my TV that's OK. I guess if I did manage to force it to 720p in the config.txt then I wouldn't be able to use 1080p if I connect it to my Dad's TV without editing config.txt, so it's probably easier to leave it unset there.