docs/envvars: Document Teflon environment variables

Add documentation describing the use of Teflon's environment variables.

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38942>

docs/envvars.rst

@@ -1264,6 +1264,34 @@ Rusticl environment variables
    Limits the amount of threads per dimension in a work-group. Useful for splitting up long running
    tasks to increase responsiveness or to simulate the lowering of huge global sizes for testing.
 
+.. _teflon-env-var:
+
+Teflon environment variables
+-----------------------------
+
+.. envvar:: TEFLON_DEBUG
+
+   If set to ``verbose``, debug information is printed to stdout.
+
+.. envvar:: TEFLON_DUMP_OUTPUT
+
+   Dumps the output buffers to a file on disk. Useful for comparing the outputs
+   from the CPU, proprietary drivers, and Mesa to check for convergence.
+
+.. envvar:: TEFLON_ENABLE_CACHE
+
+   If set, the models generated by ``test_teflon`` are stored in an on-disk cache.
+
+.. envvar:: TEFLON_TEST_DATA
+
+   Points to a directory containing models (``.tflite`` files) to be executed by
+   `test_teflon`. Usually, this is set to ``src/gallium/targets/teflon/tests``.
+
+.. envvar:: TEFLON_TEST_DELEGATE
+
+   Points to the external delegate library path. Usually, this is set to
+   ``libteflon.so``.
+
 .. _clc-env-var:
 
 clc environment variables