So I tried a few things with drm.debug=1 kernel param

When I reproduce the problem, something (plymouth?) does drm stuff before xorg, and xorg then gets EACCESS error from drm_setversion ioctl (nr=0x07) and dmesg looks like this

Apr 21 02:25:35 kujoniq kernel: [    0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.2.0-24-generic root=/dev/mapper/ssd-ubuntu--precise ro quiet drm.debug=1
Apr 21 02:25:35 kujoniq kernel: [    0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-3.2.0-24-generic root=/dev/mapper/ssd-ubuntu--precise ro quiet drm.debug=1
Apr 21 02:25:35 kujoniq kernel: [    2.487567] [drm] Initialized drm 1.1.0 20060810
Apr 21 02:25:35 kujoniq kernel: [    2.497942] [drm:drm_pci_init], 
Apr 21 02:25:35 kujoniq kernel: [    2.497952] [drm:drm_get_pci_dev], 
Apr 21 02:25:35 kujoniq kernel: [    2.497977] [drm:drm_get_minor], 
Apr 21 02:25:35 kujoniq kernel: [    2.498099] [drm:drm_get_minor], new minor assigned 64
Apr 21 02:25:35 kujoniq kernel: [    2.498101] [drm:drm_get_minor], 
Apr 21 02:25:35 kujoniq kernel: [    2.498161] [drm:drm_get_minor], new minor assigned 0
Apr 21 02:25:35 kujoniq kernel: [    2.552305] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
Apr 21 02:25:35 kujoniq kernel: [    2.552306] [drm] Driver supports precise vblank timestamp query.
Apr 21 02:25:35 kujoniq kernel: [    2.552830] [drm:drm_sysfs_connector_add], adding "VGA-1" to sysfs
Apr 21 02:25:35 kujoniq kernel: [    2.552960] [drm:drm_sysfs_hotplug_event], generating hotplug event
Apr 21 02:25:35 kujoniq kernel: [    2.567174] [drm:drm_sysfs_connector_add], adding "HDMI-A-1" to sysfs
Apr 21 02:25:35 kujoniq kernel: [    2.567194] [drm:drm_sysfs_hotplug_event], generating hotplug event
Apr 21 02:25:35 kujoniq kernel: [    2.567201] [drm:drm_sysfs_connector_add], adding "DP-1" to sysfs
Apr 21 02:25:35 kujoniq kernel: [    2.567235] [drm:drm_sysfs_hotplug_event], generating hotplug event
Apr 21 02:25:35 kujoniq kernel: [    2.676194] [drm:drm_irq_install], irq=51
Apr 21 02:25:35 kujoniq kernel: [    2.783104] fbcon: inteldrmfb (fb0) is primary device
Apr 21 02:25:35 kujoniq kernel: [    2.783492] [drm:drm_vblank_get], enabling vblank on crtc 0, ret: -22
Apr 21 02:25:36 kujoniq kernel: [    2.951148] [drm:drm_calc_timestamping_constants], crtc 3: hwmode: htotal 2080, vtotal 1235, vdisplay 1200
Apr 21 02:25:36 kujoniq kernel: [    2.951151] [drm:drm_calc_timestamping_constants], crtc 3: clock 154000 kHz framedur 16679910 linedur 13506, pixeldur 6
Apr 21 02:25:36 kujoniq kernel: [    2.957757] fb0: inteldrmfb frame buffer device
Apr 21 02:25:36 kujoniq kernel: [    2.957757] drm: registered panic notifier
Apr 21 02:25:36 kujoniq kernel: [    2.957806] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
Apr 21 02:25:36 kujoniq kernel: [    2.997507] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    2.997510] [drm:drm_open_helper], pid = 286, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    2.997514] [drm:drm_setup], 
Apr 21 02:25:36 kujoniq kernel: [    2.997517] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997520] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997523] [drm:drm_release], open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    2.997525] [drm:drm_release], pid = 286, device = 0xe200, open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    2.997528] [drm:drm_lastclose], 
Apr 21 02:25:36 kujoniq kernel: [    2.997541] [drm:drm_lastclose], driver lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    2.997542] [drm:drm_lastclose], lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    2.997546] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    2.997548] [drm:drm_open_helper], pid = 286, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    2.997549] [drm:drm_setup], 
Apr 21 02:25:36 kujoniq kernel: [    2.997551] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997553] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997556] [drm:drm_release], open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    2.997557] [drm:drm_release], pid = 286, device = 0xe200, open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    2.997559] [drm:drm_lastclose], 
Apr 21 02:25:36 kujoniq kernel: [    2.997566] [drm:drm_lastclose], driver lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    2.997568] [drm:drm_lastclose], lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    2.997571] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    2.997572] [drm:drm_open_helper], pid = 286, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    2.997574] [drm:drm_setup], 
Apr 21 02:25:36 kujoniq kernel: [    2.997576] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997578] [drm:drm_ioctl], pid=286, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997580] [drm:drm_ioctl], pid=286, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997582] [drm:drm_ioctl], pid=286, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997591] [drm:drm_ioctl], pid=286, cmd=0x80106463, nr=0x63, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997596] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997598] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997600] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997602] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997604] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997606] [drm:drm_ioctl], pid=286, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997607] [drm:drm_ioctl], ret = ffffffea
Apr 21 02:25:36 kujoniq kernel: [    2.997636] [drm:drm_ioctl], pid=286, cmd=0xc04064a0, nr=0xa0, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997639] [drm:drm_ioctl], pid=286, cmd=0xc04064a0, nr=0xa0, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    2.997642] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.056700] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.056707] [drm:drm_ioctl], pid=286, cmd=0xc01464a6, nr=0xa6, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.056710] [drm:drm_ioctl], pid=286, cmd=0xc06864a1, nr=0xa1, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.061133] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.063315] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.065568] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.087976] [drm:drm_ioctl], pid=286, cmd=0xc05064a7, nr=0xa7, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.124495] [drm:drm_ioctl], pid=286, cmd=0x641e, nr=0x1e, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134732] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    3.134735] [drm:drm_open_helper], pid = 1207, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    3.134745] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134749] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134753] [drm:drm_release], open_count = 2
Apr 21 02:25:36 kujoniq kernel: [    3.134755] [drm:drm_release], pid = 1207, device = 0xe200, open_count = 2
Apr 21 02:25:36 kujoniq kernel: [    3.134770] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    3.134772] [drm:drm_open_helper], pid = 1207, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    3.134782] [drm:drm_ioctl], pid=1207, cmd=0xc0106407, nr=0x07, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134784] [drm:drm_ioctl], ret = fffffff3
Apr 21 02:25:36 kujoniq kernel: [    3.134790] [drm:drm_ioctl], pid=1207, cmd=0xc0106407, nr=0x07, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134792] [drm:drm_ioctl], ret = fffffff3
Apr 21 02:25:36 kujoniq kernel: [    3.134793] [drm:drm_ioctl], pid=1207, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134795] [drm:drm_ioctl], pid=1207, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.134805] [drm:drm_release], open_count = 2
Apr 21 02:25:36 kujoniq kernel: [    3.134806] [drm:drm_release], pid = 1207, device = 0xe200, open_count = 2
Apr 21 02:25:36 kujoniq kernel: [    3.146138] [drm:drm_ioctl], pid=286, cmd=0x641f, nr=0x1f, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.150084] [drm:drm_release], open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    3.150086] [drm:drm_release], pid = 286, device = 0xe200, open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    3.150090] [drm:drm_lastclose], 
Apr 21 02:25:36 kujoniq kernel: [    3.150099] [drm:drm_lastclose], driver lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    3.150100] [drm:drm_lastclose], lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    3.192869] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    3.192872] [drm:drm_open_helper], pid = 1207, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    3.192876] [drm:drm_setup], 
Apr 21 02:25:36 kujoniq kernel: [    3.192883] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192887] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192890] [drm:drm_release], open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    3.192892] [drm:drm_release], pid = 1207, device = 0xe200, open_count = 1
Apr 21 02:25:36 kujoniq kernel: [    3.192895] [drm:drm_lastclose], 
Apr 21 02:25:36 kujoniq kernel: [    3.192908] [drm:drm_lastclose], driver lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    3.192909] [drm:drm_lastclose], lastclose completed
Apr 21 02:25:36 kujoniq kernel: [    3.192925] [drm:drm_stub_open], 
Apr 21 02:25:36 kujoniq kernel: [    3.192926] [drm:drm_open_helper], pid = 1207, minor = 0
Apr 21 02:25:36 kujoniq kernel: [    3.192928] [drm:drm_setup], 
Apr 21 02:25:36 kujoniq kernel: [    3.192934] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192936] [drm:drm_ioctl], pid=1207, cmd=0xc0406400, nr=0x00, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192943] [drm:drm_ioctl], pid=1207, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192945] [drm:drm_ioctl], pid=1207, cmd=0xc0106401, nr=0x01, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192955] [drm:drm_ioctl], pid=1207, cmd=0xc0106407, nr=0x07, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.192957] APW: drm_setversion called
Apr 21 02:25:36 kujoniq kernel: [    3.192974] APW: drm_setversion returned 0
Apr 21 02:25:36 kujoniq kernel: [    3.192988] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193059] [drm:drm_ioctl], pid=1207, cmd=0x80106463, nr=0x63, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193066] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193068] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193070] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193072] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193074] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193076] [drm:drm_ioctl], pid=1207, cmd=0xc0106446, nr=0x46, dev 0xe200, auth=1
Apr 21 02:25:36 kujoniq kernel: [    3.193078] [drm:drm_ioctl], ret = ffffffea