[PATCH] drm/doc: Add a few words on validation with IGT

[Tomeu Vizoso <tomeu.vizoso@collabora.com>]

Also provide some pointers for building IGT as some kernel hackers might
not be that familiar with building stuff on Linux distros.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
---
 Documentation/gpu/drm-uapi.rst | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst
index 94876938aef3..5e425ab83dc1 100644
--- a/Documentation/gpu/drm-uapi.rst
+++ b/Documentation/gpu/drm-uapi.rst
@@ -112,3 +112,40 @@ interfaces. Especially since all hardware-acceleration interfaces to
 userspace are driver specific for efficiency and other reasons these
 interfaces can be rather substantial. Hence every driver has its own
 chapter.
+
+Validating changes with IGT
+===========================
+
+There's a collection of tests that aims to cover the whole functionality of
+DRM drivers and that can be used to check that changes to DRM drivers or the
+core don't regress existing functionality. This test suite is called IGT and
+its code can be found in https://cgit.freedesktop.org/xorg/app/intel-gpu-tools.
+
+To build IGT, start by installing its build dependencies. In Debian-based
+systems::
+
+	# apt-get build-dep intel-gpu-tools
+
+And in Fedora-based systems::
+
+	# dnf builddep intel-gpu-tools
+
+Then clone the repository::
+
+	$ git clone git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
+
+Configure the build system and start the build::
+
+	$ cd intel-gpu-tools && ./autogen.sh && make -j6
+
+Download the piglit dependency::
+
+	$ ./scripts/run-tests.sh -d
+
+And run the tests::
+
+	$ ./scripts/run-tests.sh -t kms -t core -s
+
+run-tests.sh is a wrapper around piglit that will execute the tests matching
+the -t options. A report in HTML format will be available in
+./results/html/index.html. Results can be compared with piglit.
-- 
2.7.4