Running Debian 8. I have a GeForce 6600 GT and a GeForce GTX 460 SE. I was using the 340.65-2 driver, whatever the standard nvidia driver is in the repos, but that doesn't support the 6600. So I downgraded to version 304, (the legacy driver) and now I can run my three monitors without any problems, except for one. Any GL accelerated windows on the 6600 are just black. For example, glxgears gives me a black screen. OpenGL works great on the two screens being driven by the 460, but no luck with the 6600. How can I fix this?
Not interested in buying a new video card, or likely, two new video cards. I'm saving up for two very high end cards that can drive 4k displays, but that's 5 years out at least. In the mean time, I would like to get my current setup working. This has worked in the past, probably several years ago on Debian 7. I managed to play openarena across all three monitors without any issues. So it's possible :) It stopped working after I did a fresh install of Debian 8, and I haven't had a chance to work on it until recently.
.xsession-errors shows only:
Xlib: extension "RANDR" missing on display ":0.0".
but not seeing anything pop up when I try to run
glxgears on the "bad" display.
The GPU driving screen 1 is incompatible with the rest of the GPUs composing the desktop. OpenGL rendering will be disabled on screen 1.
But I know I have had this working in the past.