Your system information

• Steam client version: 1471977975
• Distribution (e.g. Ubuntu): Gentoo
• Opted into Steam client beta?: Yes (tested both)
• Have you checked for system updates?: Yes (full upgrade)

Please describe your issue in as much detail as possible:

I use fvwm2 on my linuxbox as a lightweight wm for running kodi and whatnot. Logging into steam previously worked fine a few months back (sorry don't have a better timeline), tried it a few days ago and since then it no longer works. Removing -bigpicture from the commandline brings up the regular menu, logging in works fine, launching BPM from there works fine, launching games works fine (only tested 2). Launching with -bigpicture I can hear the boot sound but the screen remains black, a long pause then the screen pops up with corruption.

used vnc on my phone to get a screenshot

the very simple /etc/system.fvwm2rc

DeskTopSize 1x1

Style *         NoTitle, NoHandles, Sticky, WindowListSkip, BorderWidth 0, StaysOnTop

Now if I wait it out, let it load and login (slowly, input is very sluggish, whole process takes a few minutes) then it goes back to normal. BPM works like it should, sometimes there is background corruption but usually not. To be clear I do not believe this is the video card dying as launching without BPM has no corruption.

Everything is launched using a lengthy custom script (usually from lircd). the meat of it is

nohup startx -- :0 >/dev/null 2>&1 &
/usr/bin/fvwm2 -f /etc/system.fvwm2rc &
exec ck-launch-session dbus-launch --sh-syntax --exit-with-session /usr/bin/steam -login login pass "steam://open/bigpicture"

I have steam on two other linux machines (desktop and optimus laptop) with kde5, no issues.

Steps for reproducing this issue:

1. launch script above.
2. fails.