OK, been fighting with this for about a month or so now. Got a PNY GeForce 750ti to replace my outdated Quadro for gaming. I didn’t realize when I purchased it that the drivers from the Ubuntu repositories, version 319, don’t support the 750ti chipset. So, after a bit of work, I disabled the built in Noveau drivers, removed the Ubuntu proprietary driver packages, and installed the latest version of the drivers from the Nvidia website.
All good so far, system boots up, X runs, games work great. Now for the problem - when I perform certain specific actions in the GUI, the X crashes with a segfault. I have searched and searched the web for anything related, and eliminated several potential problems with the glamoregl package. I found several other issues with similar symptoms, but most involved random segfaults, or otherwise didn’t apply to my situation and system. At this point, the system is 100% stable as long as I avoid certain specific operations which always result in the segfault crash. I will also point out that the system was 100% stable with the previous drivers, I only updated to get support for the 750ti.
I will attach the xorg log file and the nvidia bug report to this post, so maybe someone who knows more about the drivers can figure out if I’m missing something, or this is an actual driver bug that needs fixed. At this point, I think the problem is most likely either a problem in the actual driver itself, or an issue with the card itself. I have tried all three versions of the driver from the Nvidia website that support that 750ti, 334.21, 337.25, and 340.24.
On to the specifics of the problem - the problem can be reproduced at will by clicking inside a window for Q4Wine, VLC media player, or running Windows installers through Winetricks. Note that all three worked fine with the 319 Ubuntu driver package and my old Quadro card. The programs can run, but as soon as a window opens for any of them and I click inside of it, X crashes immediately with a segfault. I assume this is due to whatever graphics API call is being made, but I’m not sure how to figure out which one is causing the problem, or why it only occurs in certain applications. Most other programs run fine, including programs that use the nvidia VDPAU, and that use OpenGL, such as games.
I have found several other threads in various places on the web with issues that seem similar to this one, and no one seems to have found a solution. It seems to me that the issue may be an ongoing issue with the driver, but I think it may only occur with certain card and driver combinations, since some people seem to have had luck with reverting to older drivers and getting rid of the problem. However, I do not have that option, since my card is only supported by the newest 3 driver releases.