Hi there,
My dual monitor setup on the Dell Precision M4500 is broken by commit 1dce6264045cd23e9c07574ed0bb31c7dce9354f ("drm/nv50/kms: Set VBLANK time in modeset script"). I am no longer able to have more than one monitor active.
Full dmesg can be found at http://pastebin.com/7e68yMRy, but I've included an excerpt as well.
[ 0.000000] Linux version 3.18.0-rc2-00106-ga7ca10f (frans@bwaark) (gcc version 4.8.2 (Gentoo 4.8.2 p1.3r1, pie-0.5.8r1) ) #27 SMP Fri Oct 31 08:30:15 CET 2014 ... [ 1.920869] fb: switching to nouveaufb from VESA VGA [ 1.953160] Console: switching to colour dummy device 80x25 [ 1.965235] nouveau [ DEVICE][0000:01:00.0] BOOT0 : 0x0a5e00a2 [ 1.965247] nouveau [ DEVICE][0000:01:00.0] Chipset: GT216 (NVA5) [ 1.965255] nouveau [ DEVICE][0000:01:00.0] Family : NV50 [ 1.965303] nouveau [ VBIOS][0000:01:00.0] checking PRAMIN for image... [ 2.017175] tsc: Refined TSC clocksource calibration: 1595.999 MHz [ 2.060360] nouveau [ VBIOS][0000:01:00.0] ... appears to be valid [ 2.060369] nouveau [ VBIOS][0000:01:00.0] using image from PRAMIN [ 2.060704] nouveau [ VBIOS][0000:01:00.0] BIT signature found [ 2.060713] nouveau [ VBIOS][0000:01:00.0] version 70.16.5c.01.06 [ 2.075227] ACPI: Battery Slot [BAT1] (battery absent) [ 2.075329] nouveau 0000:01:00.0: irq 29 for MSI/MSI-X [ 2.075342] nouveau [ PMC][0000:01:00.0] MSI interrupts enabled [ 2.075376] nouveau [ PFB][0000:01:00.0] RAM type: DDR3 [ 2.075380] nouveau [ PFB][0000:01:00.0] RAM size: 1024 MiB [ 2.075384] nouveau [ PFB][0000:01:00.0] ZCOMP: 1920 tags [ 2.079057] nouveau [ VOLT][0000:01:00.0] GPU voltage: 930000uv [ 2.108300] nouveau [ PTHERM][0000:01:00.0] FAN control: none / external [ 2.108328] nouveau [ PTHERM][0000:01:00.0] fan management: automatic [ 2.108338] nouveau [ PTHERM][0000:01:00.0] internal sensor: yes [ 2.128401] nouveau [ CLK][0000:01:00.0] 03: core 135 MHz shader 270 MHz memory 135 MHz [ 2.128414] nouveau [ CLK][0000:01:00.0] 07: core 405 MHz shader 810 MHz memory 324 MHz [ 2.128426] nouveau [ CLK][0000:01:00.0] 0f: core 550 MHz shader 1210 MHz memory 790 MHz [ 2.128469] nouveau [ CLK][0000:01:00.0] --: core 405 MHz shader 810 MHz memory 324 MHz [ 2.129501] [TTM] Zone kernel: Available graphics memory: 4080170 kiB [ 2.129514] [TTM] Zone dma32: Available graphics memory: 2097152 kiB [ 2.129522] [TTM] Initializing pool allocator [ 2.129540] [TTM] Initializing DMA pool allocator [ 2.129575] nouveau [ DRM] VRAM: 1024 MiB [ 2.129584] nouveau [ DRM] GART: 1048576 MiB [ 2.129596] nouveau [ DRM] TMDS table version 2.0 [ 2.129605] nouveau [ DRM] DCB version 4.0 [ 2.129615] nouveau [ DRM] DCB outp 00: 048003b6 0f220014 [ 2.129626] nouveau [ DRM] DCB outp 01: 02033300 00000000 [ 2.129637] nouveau [ DRM] DCB outp 02: 028113a6 0f220010 [ 2.129647] nouveau [ DRM] DCB outp 03: 02011362 00020010 [ 2.129657] nouveau [ DRM] DCB outp 04: 088223c6 0f220010 [ 2.129667] nouveau [ DRM] DCB outp 05: 08022382 00020010 [ 2.129676] nouveau [ DRM] DCB conn 00: 00002047 [ 2.129687] nouveau [ DRM] DCB conn 01: 00101146 [ 2.129696] nouveau [ DRM] DCB conn 02: 00410246 [ 2.129705] nouveau [ DRM] DCB conn 03: 00000300 [ 2.183136] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 2.183142] [drm] Driver supports precise vblank timestamp query. [ 2.229885] nouveau [ DRM] MM: using COPY for buffer copies [ 2.545100] nouveau [ DRM] allocated 1920x1080 fb: 0x70000, bo ffff880225962c00 [ 2.545330] fbcon: nouveaufb (fb0) is primary device [ 2.596432] nouveau E[ PDISP][0000:01:00.0] INVALID_STATE [UNK05] chid 0 mthd 0x0080 data 0x00000000 [ 2.596435] nouveau E[ PDISP][0000:01:00.0] Core: [ 2.596441] nouveau E[ PDISP][0000:01:00.0] 0x0084: 0x01e00280 -> 0x00000000 [ 2.596447] nouveau E[ PDISP][0000:01:00.0] 0x0088: 0xf0000000 [ 2.596450] nouveau E[ PDISP][0000:01:00.0] Core - DAC 0: [ 2.596455] nouveau E[ PDISP][0000:01:00.0] 0x0400: 0x00000000 [ 2.596460] nouveau E[ PDISP][0000:01:00.0] 0x0404: 0x00000000 [ 2.596465] nouveau E[ PDISP][0000:01:00.0] 0x0420: 0x00010000 [ 2.596468] nouveau E[ PDISP][0000:01:00.0] Core - DAC 1: [ 2.596473] nouveau E[ PDISP][0000:01:00.0] 0x0480: 0x00000000 [ 2.596477] nouveau E[ PDISP][0000:01:00.0] 0x0484: 0x00000000 [ 2.596482] nouveau E[ PDISP][0000:01:00.0] 0x04a0: 0x00010000 [ 2.596484] nouveau E[ PDISP][0000:01:00.0] Core - DAC 2: [ 2.596489] nouveau E[ PDISP][0000:01:00.0] 0x0500: 0x00000000 [ 2.596494] nouveau E[ PDISP][0000:01:00.0] 0x0504: 0x00000000 [ 2.596498] nouveau E[ PDISP][0000:01:00.0] 0x0520: 0x00010000 [ 2.596501] nouveau E[ PDISP][0000:01:00.0] Core - SOR 0: [ 2.596506] nouveau E[ PDISP][0000:01:00.0] 0x0600: 0x00000000 [ 2.596508] nouveau E[ PDISP][0000:01:00.0] Core - SOR 1: [ 2.596513] nouveau E[ PDISP][0000:01:00.0] 0x0640: 0x00000101 [ 2.596516] nouveau E[ PDISP][0000:01:00.0] Core - SOR 2: [ 2.596521] nouveau E[ PDISP][0000:01:00.0] 0x0680: 0x00000000 [ 2.596523] nouveau E[ PDISP][0000:01:00.0] Core - SOR 3: [ 2.596528] nouveau E[ PDISP][0000:01:00.0] 0x06c0: 0x00000000 -> 0x00000102 [ 2.596531] nouveau E[ PDISP][0000:01:00.0] Core - PIOR 0: [ 2.596536] nouveau E[ PDISP][0000:01:00.0] 0x0700: 0x00000000 [ 2.596538] nouveau E[ PDISP][0000:01:00.0] Core - PIOR 1: [ 2.596543] nouveau E[ PDISP][0000:01:00.0] 0x0740: 0x00000000 [ 2.596545] nouveau E[ PDISP][0000:01:00.0] Core - PIOR 2: [ 2.596550] nouveau E[ PDISP][0000:01:00.0] 0x0780: 0x00000000 [ 2.596553] nouveau E[ PDISP][0000:01:00.0] Core - HEAD 0: ...
Hope this rings a bell, Frans