Titan X on Nvidia 349 under Linux hangs w/ 3 monitors

Crossposting from the main forums since I didn’t realize this was the main place to get Linux support, my apologies:

Hi folks,

I recently acquired a Titan X and have been using it under Linux, and I notice it’s very picky about monitor configurations – it was working OK when I had one display connected on DVI and one on HDMI, but trying to add a third display on DisplayPort results in X hanging and me needing to hard reset the machine. It doesn’t like booting this way or being hotplugged. I don’t think it’s a problem with the DP in particular, as I can boot it with just the DP and the DVI connected and that works fine too, until I try to add an HDMI display and I get a hang again.

Any idea what could be going on? I’ve made sure to disable the iGPU in the motherboard EFI just in case that was causing trouble – not really sure where to go from here. There doesn’t seem to be anything of use in Xorg logs; seems like it must be going down immediately and failing to log anything when the trouble starts. I don’t use an xorg.conf because I haven’t used one for years; xrandr seems to take care of things pretty much automatically in other cases…


Hm. I just did some more testing and it seems this may actually be related to using the DisplayPort and HDMI simultaneously, as that combination hangs with only two displays.

Further update – looks like it only happens when using the top DisplayPort! Three displays now working fine when using one of the others.

Just verified it can cleanly reboot like this, so I think my problem is solved, except I notice it’s fixed on performance level 3 now, which wasn’t happening when I only had two displays connected. It’s not a big deal because the fan isn’t too audible, but I’m surprised it’s not downclocking more. Is this the typical behaviour with three displays connected?

Aha, looks like there’s already a thread about that: https://devtalk.nvidia.com/default/topic/547761/linux/powermizer-power-levels-stuck-at-max-on-gtx-650-with-319-xx-325-xx-drivers/2/

I’d love a fix for this …

I have this issue as well; https://devtalk.nvidia.com/default/topic/876860/linux/gtx-970-connecting-3-monitors-causes-a-hang/