Can't get multiple displays with Nouveau drivers

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Since installing Fedora 25, I have never been able to get multi-monitor support to work without installing Nvidia's proprietary drivers. Furthermore, when I'm on Nouveau, my cinnamon environment warns me that it has reverted to software rendering as a result of some issues with video drivers. Now that Nvidia drivers have begun causing serious issues (and I hate the idea of 'proprietary' drivers in Linux), I have uninstalled Nvidia and am trying to solve how to get Nouveau to play ball. I am on a GTX 900 series, and followed the RPMFusion Guide to a tee. I also cleared blacklisting out of grub cfg and rebuilt grub successfully, and the driver appears to load:

lsmod |grep nouveau

Reveals several entries

modprobe nouveau

Shows no errors.

grep nouveau /etc/modprobe.d/*

Shows no blacklisted entries.

Also it appears that X server is doing its job:

$ cat /var/log/Xorg.0.log | grep nouveau
[    36.123] (==) Matched nouveau as autoconfigured driver 0
[    36.123] (II) LoadModule: "nouveau"
[    36.123] (II) Loading /usr/lib64/xorg/modules/drivers/nouveau_drv.so
[    36.126] (II) Module nouveau: vendor="X.Org Foundation"

Does anyone have any advice? Thank you.