http://cgit.freedesktop.org/xorg/xserver/commit/?id=c99fb550e06207e83ec89463fe32bd6bceca45f8 Please include this patch into xorg-server builds. The recent stabilization of Xorg 1.17 broke this feature (which is fixed again in 1.18). Reproducible: Always Steps to Reproduce: 1. Boot with nouveau blacklisted, intel used as primary 2. Set AutoAddGPU=false in xorg.conf 3. modprobe nouveau Actual Results: Observe how Xorg grabs onto the newly availabel GPU device, with the modesetting driver. And in my case exited for good measure, but I don't know if that's a separate issue, I didn't see a crash in the log. Expected Results: X ignores the newly added GPU, making it possible to later rmmod nouveau without restarting X. [IP-] [ ] x11-base/xorg-server-1.17.4:0/1.17.4 xorg-server built with +udev [which is the default I believe] $ /usr/sbin/lspci -nn -d ::300 00:02.0 VGA compatible controller [0300]: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:0412] (rev 06) 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK208 [GeForce GT 720] [10de:1286] (rev a1) Screens connected to Intel GPU, use the NVIDIA GPU via DRI3 (which doesn't require X to have any knowledge of the GPU, unlike with DRI2).
1.18.4 is stable and includes this.