Created attachment 40160 [details]
Simple glut program which produces the error

When accessing a sampler with the built in texture functions in a vertex shader program, the Mesa driver prints the following:

Mesa 7.9-devel implementation error: Unsupported opcode 81 (TEX) in vertex shader
Please report at bugzilla.freedesktop.org

I have attached a minimal GLUT program which reproduces this error on my hardware. The vertex shader samples a grey 2D texture and scales the x value of the vertices of a quad, which should result in a vertical white rectangle.  What happens instead is the exception is printed and the quad remains a square.

System info:
Computer model: Lenovo Thinkpad Edge 13 (Intel)
Graphics card: Intel GMA 4500MHD
Operating system: Ubuntu Maverick Meerkat 10.10 64-bit

OpenGL/GLX version info:
server glx vendor string: SGI
server glx version string: 1.4
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
GLX version: 1.4
OpenGL vendor string: Tungsten Graphics, Inc
OpenGL renderer string: Mesa DRI Mobile Intel® GM45 Express Chipset GEM 20100330 DEVELOPMENT 
OpenGL version string: 2.1 Mesa 7.9-devel
OpenGL shading language version string: 1.20


The same GLUT program runs correctly on an Intel Macbook Pro with a NVIDIA GeForce 9500M.