Here are the logs without and with drm debug option set:
[0.000000] Initializing cgroup subsys cpuset [0.000000] Initializing cgroup subsys cpu [0.000000] Linux version 2.6.35-31-generic (buildd@pluot) (gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5) ) #62+lp722806thor4-Ubuntu SMP Fri Nov 25 11:50:56 UTC 2011 (Ubuntu 2.6.35-31.62+lp722806thor4-generic 2.6.35.13) [0.000000] Command line: BOOT_IMAGE=/vmlinuz-2.6.35-31-generic root=UUID=bd9acbc2-0ada-404f-9864-158f93de9ed5 ro crashkernel=384M-2G:64M,2G-:128M quiet splash
...
[8.459216] [drm] Radeon Display Connectors [8.459218] [drm] Connector 0: [8.459220] [drm] VGA [8.459223] [drm] DDC: 0x7e50 0x7e40 0x7e54 0x7e44 0x7e58 0x7e48 0x7e5c 0x7e4c [8.459225] [drm] Encoders: [8.459227] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [8.459229] [drm] Connector 1: [8.459231] [drm] S-video [8.459232] [drm] Encoders: [8.459234] [drm] TV1: INTERNAL_KLDSCP_DAC1 [8.459236] [drm] Connector 2: [8.459238] [drm] HDMI-A [8.459239] [drm] HPD2 [8.459242] [drm] DDC: 0x7e40 0x7e60 0x7e44 0x7e64 0x7e48 0x7e68 0x7e4c 0x7e6c [8.459244] [drm] Encoders: [8.459246] [drm] DFP2: INTERNAL_DDI [8.459248] [drm] Connector 3: [8.459249] [drm] DVI-D [8.459252] [drm] DDC: 0x7e40 0x7e50 0x7e44 0x7e54 0x7e48 0x7e58 0x7e4c 0x7e5c [8.459254] [drm] Encoders: [8.459256] [drm] DFP3: INTERNAL_LVTM1 [8.593100] i2c /dev entries driver [8.721280] Raw EDID: [8.721324] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721327] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721330] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721332] <3>00 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00 ................ [8.721335] <3>00 00 00 1f 03 00 00 00 00 07 00 00 00 01 00 00 ................ [8.721338] <3>00 00 0f 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721340] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721343] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.721345] [8.721383] radeon 0000:01:05.0: HDMI-A-1: EDID block 0 invalid. [8.721387] [drm:radeon_dvi_detect] HDMI-A-1: probed a monitor, DDC responded but no|invalid EDID [8.721428] [drm:radeon_dvi_detect] HDMI-A-1: detected RS690 floating bus bug, stopping ddc detect [8.871708] [drm] fb mappable at 0xF0040000 [8.871713] [drm] vram apper at 0xF0000000 [8.871715] [drm] size 5242880 [8.871717] [drm] fb depth is 24 [8.871719] [drm] pitch is 5120 [8.912957] Console: switching to colour frame buffer device 160x64 [8.925225] fb0: radeondrmfb frame buffer device [8.925228] drm: registered panic notifier [8.964597] [drm] Initialized radeon 2.5.0 20080528 for 0000:01:05.0 on minor 0
[0.000000] Initializing cgroup subsys cpuset [0.000000] Initializing cgroup subsys cpu [0.000000] Linux version 2.6.35-31-generic (buildd@pluot) (gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5) ) #62+lp722806thor4-Ubuntu SMP Fri Nov 25 11:50:56 UTC 2011 (Ubuntu 2.6.35-31.62+lp722806thor4-generic 2.6.35.13) [0.000000] Command line: BOOT_IMAGE=/vmlinuz-2.6.35-31-generic root=UUID=bd9acbc2-0ada-404f-9864-158f93de9ed5 ro crashkernel=384M-2G:64M,2G-:128M quiet splash drm.debug=14 log_buf_len=16M
...
[8.320490] [drm] Radeon Display Connectors [8.320492] [drm] Connector 0: [8.320494] [drm] VGA [8.320498] [drm] DDC: 0x7e50 0x7e40 0x7e54 0x7e44 0x7e58 0x7e48 0x7e5c 0x7e4c [8.320500] [drm] Encoders: [8.320502] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [8.320504] [drm] Connector 1: [8.320506] [drm] S-video [8.320508] [drm] Encoders: [8.320510] [drm] TV1: INTERNAL_KLDSCP_DAC1 [8.320512] [drm] Connector 2: [8.320514] [drm] HDMI-A [8.320515] [drm] HPD2 [8.320518] [drm] DDC: 0x7e40 0x7e60 0x7e44 0x7e64 0x7e48 0x7e68 0x7e4c 0x7e6c [8.320521] [drm] Encoders: [8.320523] [drm] DFP2: INTERNAL_DDI [8.320525] [drm] Connector 3: [8.320526] [drm] DVI-D [8.320529] [drm] DDC: 0x7e40 0x7e50 0x7e44 0x7e54 0x7e48 0x7e58 0x7e4c 0x7e5c [8.320532] [drm] Encoders: [8.320534] [drm] DFP3: INTERNAL_LVTM1 [8.320598] [drm:drm_helper_probe_single_connector_modes], VGA-1 [8.410041] [drm:drm_helper_probe_single_connector_modes], VGA-1 is disconnected [8.410049] [drm:drm_helper_probe_single_connector_modes], SVIDEO-1 [8.479510] i2c /dev entries driver [8.500081] [drm:drm_helper_probe_single_connector_modes], SVIDEO-1 is disconnected [8.500090] [drm:drm_helper_probe_single_connector_modes], HDMI-A-1 [8.563878] Raw EDID: [8.563922] <3>00 00 07 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563926] <3>00 00 ff 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563929] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563932] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563934] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563937] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563940] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563943] <3>00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [8.563945] [8.563983] radeon 0000:01:05.0: HDMI-A-1: EDID block 0 invalid. [8.563987] [drm:radeon_dvi_detect] HDMI-A-1: probed a monitor, DDC responded but no|invalid EDID [8.564028] [drm:radeon_dvi_detect] HDMI-A-1: detected RS690 floating bus bug, stopping ddc detect [8.564074] [drm:drm_helper_probe_single_connector_modes], HDMI-A-1 is disconnected [8.564080] [drm:drm_helper_probe_single_connector_modes], DVI-D-1 [8.624077] [drm:drm_helper_probe_single_connector_modes], Probed modes for DVI-D-1 [8.624083] [drm:drm_mode_debug_printmodeline], Modeline 17:"1280x1024" 60 108000 1280 1328 1440 1688 1024 1025 1028 1066 0x48 0x5 ...