Comment 17 for bug 1386695

Another update:

I tried running with a secondary monitor. Unfortunately under that setup the nouveau.nofbaccel=1 workaround doesn't cut it anymore, and only one monitor works after resume. Trying to unplug and replug or use xrandr after this has happened doesn't make the other monitor work and once even left me with no screen. I found some new kernel messages, in particular:

<6>[ 0.336621] nouveau [ PFB][0000:01:00.0] RAM type: GDDR3
<6>[ 0.336623] nouveau [ PFB][0000:01:00.0] RAM size: 512 MiB
<3>[ 0.336620] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000007 FAULT at 0x00e180
--snip--
<6>[ 0.365519] nouveau [ DRM] VRAM: 512 MiB
<6>[ 0.365521] nouveau [ DRM] GART: 1048576 MiB
--snip--
<3>[ 0.366886] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e070
<3>[ 0.368257] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e070

right after nouveau loads, another:

<6>[ 75.935933] nouveau [ DRM] suspending console...
<6>[ 75.935944] nouveau [ DRM] suspending display...
<6>[ 75.936012] nouveau [ DRM] evicting buffers...
<6>[ 76.206568] nouveau [ DRM] waiting for kernel channels to go idle...
<6>[ 76.206573] nouveau [ DRM] suspending client object trees...
<6>[ 76.207261] nouveau [ DRM] suspending kernel object tree...
<3>[ 76.267516] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e070

immediately before suspend and:

<6>[ 78.110864] nouveau [ DRM] re-enabling device...
<6>[ 78.110870] nouveau [ DRM] resuming kernel object tree...
<6>[ 78.110882] nouveau [ VBIOS][0000:01:00.0] running init tables
<3>[ 78.200040] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e074
<6>[ 78.274292] nouveau [ VOLT][0000:01:00.0] GPU voltage: 1000000uv
<6>[ 78.274303] nouveau [ PTHERM][0000:01:00.0] fan management: automatic
<6>[ 78.274378] nouveau [ CLK][0000:01:00.0] --: core 399 MHz shader 810 MHz memory 499 MHz
<3>[ 78.275977] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e070
<3>[ 78.277301] nouveau E[ PBUS][0000:01:00.0] MMIO write of 0x00000000 FAULT at 0x00e070
<6>[ 78.277474] nouveau [ DRM] resuming client object trees...
<6>[ 78.277902] nouveau [ DRM] resuming display...

on resume. Maybe this is another bug?

So now I'm using linux-lts 3.14.22. No problems there, suspend and multi monitor setups work great.