drm: Add initial ci/ subdirectory

Developers can easily execute several tests on different devices
by just pushing their branch to their fork in a repository hosted
on gitlab.freedesktop.org which has an infrastructure to run jobs
in several runners and farms with different devices.

There are also other automated tools that uprev dependencies,
monitor the infra, and so on that are already used by the Mesa
project, and we can reuse them too.

Also, store expectations about what the DRM drivers are supposed
to pass in the IGT test suite. By storing the test expectations
along with the code, we can make sure both stay in sync with each
other so we can know when a code change breaks those expectations.

Also, include a configuration file that points to the out-of-tree
CI scripts.

This will allow all contributors to drm to reuse the infrastructure
already in gitlab.freedesktop.org to test the driver on several
generations of the hardware.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Acked-by: Daniel Stone <daniels@collabora.com>
Acked-by: Rob Clark <robdclark@gmail.com>
Tested-by: Rob Clark <robdclark@gmail.com>
[sima: Remove top-level empty file test, spotted by sfr]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20230811171953.176431-1-helen.koike@collabora.com

2 files changed, 145 insertions, 0 deletions

diff --git a/Documentation/gpu/automated_testing.rst b/Documentation/gpu/automated_testing.rst
new file mode 100644
index 000000000000..1b87b802ac7f
--- /dev/null
+++ b/Documentation/gpu/automated_testing.rst
@@ -0,0 +1,144 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+=========================================
+Automated testing of the DRM subsystem
+=========================================
+
+Introduction
+============
+
+Making sure that changes to the core or drivers don't introduce regressions can
+be very time-consuming when lots of different hardware configurations need to
+be tested. Moreover, it isn't practical for each person interested in this
+testing to have to acquire and maintain what can be a considerable amount of
+hardware.
+
+Also, it is desirable for developers to check for regressions in their code by
+themselves, instead of relying on the maintainers to find them and then
+reporting back.
+
+There are facilities in gitlab.freedesktop.org to automatically test Mesa that
+can be used as well for testing the DRM subsystem. This document explains how
+people interested in testing it can use this shared infrastructure to save
+quite some time and effort.
+
+
+Relevant files
+==============
+
+drivers/gpu/drm/ci/gitlab-ci.yml
+--------------------------------
+
+This is the root configuration file for GitLab CI. Among other less interesting
+bits, it specifies the specific version of the scripts to be used. There are
+some variables that can be modified to change the behavior of the pipeline:
+
+DRM_CI_PROJECT_PATH
+    Repository that contains the Mesa software infrastructure for CI
+
+DRM_CI_COMMIT_SHA
+    A particular revision to use from that repository
+
+UPSTREAM_REPO
+    URL to git repository containing the target branch
+
+TARGET_BRANCH
+    Branch to which this branch is to be merged into
+
+IGT_VERSION
+    Revision of igt-gpu-tools being used, from
+    https://gitlab.freedesktop.org/drm/igt-gpu-tools
+
+drivers/gpu/drm/ci/testlist.txt
+-------------------------------
+
+IGT tests to be run on all drivers (unless mentioned in a driver's *-skips.txt
+file, see below).
+
+drivers/gpu/drm/ci/${DRIVER_NAME}-${HW_REVISION}-fails.txt
+----------------------------------------------------------
+
+Lists the known failures for a given driver on a specific hardware revision.
+
+drivers/gpu/drm/ci/${DRIVER_NAME}-${HW_REVISION}-flakes.txt
+-----------------------------------------------------------
+
+Lists the tests that for a given driver on a specific hardware revision are
+known to behave unreliably. These tests won't cause a job to fail regardless of
+the result. They will still be run.
+
+drivers/gpu/drm/ci/${DRIVER_NAME}-${HW_REVISION}-skips.txt
+-----------------------------------------------------------
+
+Lists the tests that won't be run for a given driver on a specific hardware
+revision. These are usually tests that interfere with the running of the test
+list due to hanging the machine, causing OOM, taking too long, etc.
+
+
+How to enable automated testing on your tree
+============================================
+
+1. Create a Linux tree in https://gitlab.freedesktop.org/ if you don't have one
+yet
+
+2. In your kernel repo's configuration (eg.
+https://gitlab.freedesktop.org/janedoe/linux/-/settings/ci_cd), change the
+CI/CD configuration file from .gitlab-ci.yml to
+drivers/gpu/drm/ci/gitlab-ci.yml.
+
+3. Next time you push to this repository, you will see a CI pipeline being
+created (eg. https://gitlab.freedesktop.org/janedoe/linux/-/pipelines)
+
+4. The various jobs will be run and when the pipeline is finished, all jobs
+should be green unless a regression has been found.
+
+
+How to update test expectations
+===============================
+
+If your changes to the code fix any tests, you will have to remove one or more
+lines from one or more of the files in
+drivers/gpu/drm/ci/${DRIVER_NAME}_*_fails.txt, for each of the test platforms
+affected by the change.
+
+
+How to expand coverage
+======================
+
+If your code changes make it possible to run more tests (by solving reliability
+issues, for example), you can remove tests from the flakes and/or skips lists,
+and then the expected results if there are any known failures.
+
+If there is a need for updating the version of IGT being used (maybe you have
+added more tests to it), update the IGT_VERSION variable at the top of the
+gitlab-ci.yml file.
+
+
+How to test your changes to the scripts
+=======================================
+
+For testing changes to the scripts in the drm-ci repo, change the
+DRM_CI_PROJECT_PATH and DRM_CI_COMMIT_SHA variables in
+drivers/gpu/drm/ci/gitlab-ci.yml to match your fork of the project (eg.
+janedoe/drm-ci). This fork needs to be in https://gitlab.freedesktop.org/.
+
+
+How to incorporate external fixes in your testing
+=================================================
+
+Often, regressions in other trees will prevent testing changes local to the
+tree under test. These fixes will be automatically merged in during the build
+jobs from a branch in the target tree that is named as
+${TARGET_BRANCH}-external-fixes.
+
+If the pipeline is not in a merge request and a branch with the same name
+exists in the local tree, commits from that branch will be merged in as well.
+
+
+How to deal with automated testing labs that may be down
+========================================================
+
+If a hardware farm is down and thus causing pipelines to fail that would
+otherwise pass, one can disable all jobs that would be submitted to that farm
+by editing the file at
+https://gitlab.freedesktop.org/gfx-ci/lab-status/-/blob/main/lab-status.yml.
diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst
index eee5996acf2c..e45ff0915246 100644
--- a/Documentation/gpu/index.rst
+++ b/Documentation/gpu/index.rst
@@ -17,6 +17,7 @@ GPU Driver Developer's Guide
    backlight
    vga-switcheroo
    vgaarbiter
+   automated_testing
    todo
    rfc/index