When I run this line in shell, I receive the following output message: $ glxgears Mesa 9.1.3 implementation error: Trying to enable/disable unknown extension GL_ANGLE_texture_compression_dxt Please report at bugs.freedesktop.org Mesa 9.1.3 implementation error: Trying to enable unknown extension: GL_ANGLE_texture_compression_dxt Please report at bugs.freedesktop.org 2274 frames in 5.0 seconds = 454.686 FPS
It looks like you have the environment variable MESA_EXTENSION_OVERRIDE set to GL_ANGLE_texture_compression_dxt (which isn't an extension, only GL_ANGLE_texture_compression_dxt3 and GL_ANGLE_texture_compression_dxt5 are). Closing as INVALID, unless my assumption was wrong.
Hm, it's more complicated that this. GL_ANGLE_texture_compression_dxt is an extension spec that lists *dxt{1,3,5} as name strings. Maybe we should force on these when GL_ANGLE_texture_compression_dxt is specified as an extension override?
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