From xrandr --verbose under Oneric (where I'm not having this problem) on the same machine:
EDID: 00ffffffffffff005a6309e801010101 260d01031d281ec0eacc58a054479925 0f484cffff80a94f81996159714fc14f c940d140e140a659403062b0324040c0 130086221100001e000000ff0034324b 3033333830303333350a000000fd0032 b41e6e1a000a202020202020000000fc 004732323066620a20202020202000df
More info later.
From xrandr --verbose under Oneric (where I'm not having this problem) on the same machine:
EDID:
00fffffffffff f005a6309e80101 0101
260d01031d281 ec0eacc58a05447 9925
0f484cffff80a 94f81996159714f c14f
c940d140e140a 659403062b03240 40c0
1300862211000 01e000000ff0034 324b
3033333830303 333350a000000fd 0032
b41e6e1a000a2 020202020200000 00fc
0047323230666 20a202020202020 00df
More info later.