Tag: environment variables
Its time for a quick howto – for some time I have been sticking with older NVIDIA driver releases on my Ubuntu machines do to a buffer overrun error on some older games when using driver sets newer than 185.18.36. The interesting thing is that equivalent Windows drivers exhibited the same problem, except that eventually the issue was fixed on Windows. After doing some searching I came across the answer to fix this issue – thanks to Conky on nvnews.net.
The problem stems from the newer drivers reporting a GL Extension Version String that is too long for some older programs to process, thus resulting in the buffer overrun. To fix this, NVIDIA included an environment variable that can be set to report older (and thus shorter) version strings.
The game I was having the most trouble with was Call of Duty 1. I know, why would I want to play such an old version? I am a COD addict and still play COD1 all the way up to the current COD:MW2. Under linux, COD1 must be run using Wine. Normally cd’ing to the Call of Duty Directory and running the following command will start the game:
However, using NVIDIA 256.53 (or anything beyond the 185.18.36 driver version) will result in the buffer overrun error. To fix this issue, change your startup command to the following:
__GL_ExtensionStringVersion=17700 wine CoDSP.exe
The __GL_ExtensionStringVersion is an environment variable that in this case is set to 17700. What this is doing it telling the NVIDIA driver to report the GL_ExtensionString as if the driver was from the 177.00 series. This effectively eliminates the overrun error and allows the game to start.
This issue, is mentioned in the NVIDIA driver readme file (here is the snippet), as was kindly pointed out by Conky over at nvnews.net:
Some applications, such as Quake 3, crash after querying the OpenGL extension string
Some applications have bugs that are triggered when the extension string is longer than a certain size. As more features are added to the driver, the length of this string increases and can trigger these sorts of bugs.
You can limit the extensions listed in the OpenGL extension string to the ones that appeared in a particular version of the driver by setting the __GL_ExtensionStringVersion environment variable to a particular version number. For example,
will run Quake 3 with the extension string that appeared in the 177.* driver series. Limiting the size of the extension string can work around this sort of application bug.
So, there you have it. I learned that you’re never “too good” read the readme files.