<li>tes - dump shader assembly for tessellation evaluation shaders</li>
<li>tex - emit messages about textures.</li>
<li>urb - emit messages about URB setup</li>
- <li>vec4 - force vec4 mode in vertex shader</li>
<li>vert - emit messages about vertex assembly</li>
<li>vs - dump shader assembly for vertex shaders</li>
</ul>
+<li>INTEL_SCALAR_VS (or TCS, TES, GS) - force scalar/vec4 mode for a shader stage (Gen8-9 only)</li>
<li>INTEL_PRECISE_TRIG - if set to 1, true or yes, then the driver prefers
accuracy over performance in trig functions.</li>
</ul>
(will often result in incorrect rendering).
<li>SVGA_DEBUG - for dumping shaders, constant buffers, etc. See the code
for details.
+<li>SVGA_EXTRA_LOGGING - if set, enables extra logging to the vmware.log file,
+such as the OpenGL program's name and command line arguments.
<li>See the driver code for other, lesser-used variables.
</ul>