[PATCH v5 3/9] drm: selftest: convert drm_rect selftest to KUnit

[Maíra Canal]

Considering the current adoption of the KUnit framework, convert the
DRM rect selftest to the KUnit API.

Co-developed-by: Carlos Veras <carlos.craveiro@xxxxxx>
Signed-off-by: Carlos Veras <carlos.craveiro@xxxxxx>
Co-developed-by: Matheus Vieira <matheus.vieira.g@xxxxxx>
Signed-off-by: Matheus Vieira <matheus.vieira.g@xxxxxx>
Tested-by: David Gow <davidgow@xxxxxxxxxx>
Acked-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Signed-off-by: Maíra Canal <maira.canal@xxxxxx>
---
 drivers/gpu/drm/selftests/Makefile            |   2 +-
 .../gpu/drm/selftests/drm_modeset_selftests.h |   4 -
 .../drm/selftests/test-drm_modeset_common.h   |   4 -
 drivers/gpu/drm/selftests/test-drm_rect.c     | 223 ------------------
 drivers/gpu/drm/tests/Makefile                |   2 +-
 drivers/gpu/drm/tests/drm_rect_test.c         | 214 +++++++++++++++++
 6 files changed, 216 insertions(+), 233 deletions(-)
 delete mode 100644 drivers/gpu/drm/selftests/test-drm_rect.c
 create mode 100644 drivers/gpu/drm/tests/drm_rect_test.c

diff --git a/drivers/gpu/drm/selftests/Makefile b/drivers/gpu/drm/selftests/Makefile
index 8633bb9ea717..8a794914e328 100644
--- a/drivers/gpu/drm/selftests/Makefile
+++ b/drivers/gpu/drm/selftests/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 test-drm_modeset-y := test-drm_modeset_common.o test-drm_plane_helper.o \
                       test-drm_format.o test-drm_framebuffer.o \
-		      test-drm_dp_mst_helper.o test-drm_rect.o
+		      test-drm_dp_mst_helper.o
 
 obj-$(CONFIG_DRM_DEBUG_SELFTEST) += test-drm_mm.o test-drm_modeset.o \
 				    test-drm_buddy.o
diff --git a/drivers/gpu/drm/selftests/drm_modeset_selftests.h b/drivers/gpu/drm/selftests/drm_modeset_selftests.h
index 4787b3b70709..a3ca90307364 100644
--- a/drivers/gpu/drm/selftests/drm_modeset_selftests.h
+++ b/drivers/gpu/drm/selftests/drm_modeset_selftests.h
@@ -6,10 +6,6 @@
  *
  * Tests are executed in order by igt/drm_selftests_helper
  */
-selftest(drm_rect_clip_scaled_div_by_zero, igt_drm_rect_clip_scaled_div_by_zero)
-selftest(drm_rect_clip_scaled_not_clipped, igt_drm_rect_clip_scaled_not_clipped)
-selftest(drm_rect_clip_scaled_clipped, igt_drm_rect_clip_scaled_clipped)
-selftest(drm_rect_clip_scaled_signed_vs_unsigned, igt_drm_rect_clip_scaled_signed_vs_unsigned)
 selftest(check_plane_state, igt_check_plane_state)
 selftest(check_drm_format_block_width, igt_check_drm_format_block_width)
 selftest(check_drm_format_block_height, igt_check_drm_format_block_height)
diff --git a/drivers/gpu/drm/selftests/test-drm_modeset_common.h b/drivers/gpu/drm/selftests/test-drm_modeset_common.h
index c29354e59cec..42a10d7da51c 100644
--- a/drivers/gpu/drm/selftests/test-drm_modeset_common.h
+++ b/drivers/gpu/drm/selftests/test-drm_modeset_common.h
@@ -16,10 +16,6 @@
 
 #define FAIL_ON(x) FAIL((x), "%s", "FAIL_ON(" __stringify(x) ")\n")
 
-int igt_drm_rect_clip_scaled_div_by_zero(void *ignored);
-int igt_drm_rect_clip_scaled_not_clipped(void *ignored);
-int igt_drm_rect_clip_scaled_clipped(void *ignored);
-int igt_drm_rect_clip_scaled_signed_vs_unsigned(void *ignored);
 int igt_check_plane_state(void *ignored);
 int igt_check_drm_format_block_width(void *ignored);
 int igt_check_drm_format_block_height(void *ignored);
diff --git a/drivers/gpu/drm/selftests/test-drm_rect.c b/drivers/gpu/drm/selftests/test-drm_rect.c
deleted file mode 100644
index 3a5ff38321f4..000000000000
--- a/drivers/gpu/drm/selftests/test-drm_rect.c
+++ /dev/null
@@ -1,223 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Test cases for the drm_rect functions
- */
-
-#define pr_fmt(fmt) "drm_rect: " fmt
-
-#include <linux/limits.h>
-
-#include <drm/drm_rect.h>
-
-#include "test-drm_modeset_common.h"
-
-int igt_drm_rect_clip_scaled_div_by_zero(void *ignored)
-{
-	struct drm_rect src, dst, clip;
-	bool visible;
-
-	/*
-	 * Make sure we don't divide by zero when dst
-	 * width/height is zero and dst and clip do not intersect.
-	 */
-	drm_rect_init(&src, 0, 0, 0, 0);
-	drm_rect_init(&dst, 0, 0, 0, 0);
-	drm_rect_init(&clip, 1, 1, 1, 1);
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-	FAIL(visible, "Destination not be visible\n");
-	FAIL(drm_rect_visible(&src), "Source should not be visible\n");
-
-	drm_rect_init(&src, 0, 0, 0, 0);
-	drm_rect_init(&dst, 3, 3, 0, 0);
-	drm_rect_init(&clip, 1, 1, 1, 1);
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-	FAIL(visible, "Destination not be visible\n");
-	FAIL(drm_rect_visible(&src), "Source should not be visible\n");
-
-	return 0;
-}
-
-int igt_drm_rect_clip_scaled_not_clipped(void *ignored)
-{
-	struct drm_rect src, dst, clip;
-	bool visible;
-
-	/* 1:1 scaling */
-	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
-	drm_rect_init(&dst, 0, 0, 1, 1);
-	drm_rect_init(&clip, 0, 0, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 1 << 16 ||
-	     src.y1 != 0 || src.y2 != 1 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 1 ||
-	     dst.y1 != 0 || dst.y2 != 1,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 2:1 scaling */
-	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
-	drm_rect_init(&dst, 0, 0, 1, 1);
-	drm_rect_init(&clip, 0, 0, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 2 << 16 ||
-	     src.y1 != 0 || src.y2 != 2 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 1 ||
-	     dst.y1 != 0 || dst.y2 != 1,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 1:2 scaling */
-	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 0, 0, 2, 2);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 1 << 16 ||
-	     src.y1 != 0 || src.y2 != 1 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 2 ||
-	     dst.y1 != 0 || dst.y2 != 2,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	return 0;
-}
-
-int igt_drm_rect_clip_scaled_clipped(void *ignored)
-{
-	struct drm_rect src, dst, clip;
-	bool visible;
-
-	/* 1:1 scaling top/left clip */
-	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 0, 0, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 1 << 16 ||
-	     src.y1 != 0 || src.y2 != 1 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 1 ||
-	     dst.y1 != 0 || dst.y2 != 1,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 1:1 scaling bottom/right clip */
-	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 1, 1, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
-	     src.y1 != 1 << 16 || src.y2 != 2 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 1 || dst.x2 != 2 ||
-	     dst.y1 != 1 || dst.y2 != 2,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 2:1 scaling top/left clip */
-	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 0, 0, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 2 << 16 ||
-	     src.y1 != 0 || src.y2 != 2 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 1 ||
-	     dst.y1 != 0 || dst.y2 != 1,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 2:1 scaling bottom/right clip */
-	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 1, 1, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 2 << 16 || src.x2 != 4 << 16 ||
-	     src.y1 != 2 << 16 || src.y2 != 4 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 1 || dst.x2 != 2 ||
-	     dst.y1 != 1 || dst.y2 != 2,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 1:2 scaling top/left clip */
-	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
-	drm_rect_init(&dst, 0, 0, 4, 4);
-	drm_rect_init(&clip, 0, 0, 2, 2);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 0 || src.x2 != 1 << 16 ||
-	     src.y1 != 0 || src.y2 != 1 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 0 || dst.x2 != 2 ||
-	     dst.y1 != 0 || dst.y2 != 2,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	/* 1:2 scaling bottom/right clip */
-	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
-	drm_rect_init(&dst, 0, 0, 4, 4);
-	drm_rect_init(&clip, 2, 2, 2, 2);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
-	     src.y1 != 1 << 16 || src.y2 != 2 << 16,
-	     "Source badly clipped\n");
-	FAIL(dst.x1 != 2 || dst.x2 != 4 ||
-	     dst.y1 != 2 || dst.y2 != 4,
-	     "Destination badly clipped\n");
-	FAIL(!visible, "Destination should be visible\n");
-	FAIL(!drm_rect_visible(&src), "Source should be visible\n");
-
-	return 0;
-}
-
-int igt_drm_rect_clip_scaled_signed_vs_unsigned(void *ignored)
-{
-	struct drm_rect src, dst, clip;
-	bool visible;
-
-	/*
-	 * 'clip.x2 - dst.x1 >= dst width' could result a negative
-	 * src rectangle width which is no longer expected by the
-	 * code as it's using unsigned types. This could lead to
-	 * the clipped source rectangle appering visible when it
-	 * should have been fully clipped. Make sure both rectangles
-	 * end up invisible.
-	 */
-	drm_rect_init(&src, 0, 0, INT_MAX, INT_MAX);
-	drm_rect_init(&dst, 0, 0, 2, 2);
-	drm_rect_init(&clip, 3, 3, 1, 1);
-
-	visible = drm_rect_clip_scaled(&src, &dst, &clip);
-
-	FAIL(visible, "Destination should not be visible\n");
-	FAIL(drm_rect_visible(&src), "Source should not be visible\n");
-
-	return 0;
-}
diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
index b3e73d674c67..f2eced30a955 100644
--- a/drivers/gpu/drm/tests/Makefile
+++ b/drivers/gpu/drm/tests/Makefile
@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_DRM_KUNIT_TEST) += drm_format_helper_test.o drm_damage_helper_test.o \
-	drm_cmdline_parser_test.o
+	drm_cmdline_parser_test.o drm_rect_test.o
diff --git a/drivers/gpu/drm/tests/drm_rect_test.c b/drivers/gpu/drm/tests/drm_rect_test.c
new file mode 100644
index 000000000000..c1dbefd49a4c
--- /dev/null
+++ b/drivers/gpu/drm/tests/drm_rect_test.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test cases for the drm_rect functions
+ *
+ * Copyright (c) 2022 Maíra Canal <mairacanal@xxxxxxxxxx>
+ */
+
+#include <kunit/test.h>
+
+#include <drm/drm_rect.h>
+
+static void igt_drm_rect_clip_scaled_div_by_zero(struct kunit *test)
+{
+	struct drm_rect src, dst, clip;
+	bool visible;
+
+	/*
+	 * Make sure we don't divide by zero when dst
+	 * width/height is zero and dst and clip do not intersect.
+	 */
+	drm_rect_init(&src, 0, 0, 0, 0);
+	drm_rect_init(&dst, 0, 0, 0, 0);
+	drm_rect_init(&clip, 1, 1, 1, 1);
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination not be visible\n");
+	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");
+
+	drm_rect_init(&src, 0, 0, 0, 0);
+	drm_rect_init(&dst, 3, 3, 0, 0);
+	drm_rect_init(&clip, 1, 1, 1, 1);
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination not be visible\n");
+	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");
+}
+
+static void igt_drm_rect_clip_scaled_not_clipped(struct kunit *test)
+{
+	struct drm_rect src, dst, clip;
+	bool visible;
+
+	/* 1:1 scaling */
+	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
+	drm_rect_init(&dst, 0, 0, 1, 1);
+	drm_rect_init(&clip, 0, 0, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
+			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
+			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 2:1 scaling */
+	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
+	drm_rect_init(&dst, 0, 0, 1, 1);
+	drm_rect_init(&clip, 0, 0, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 2 << 16 ||
+			       src.y1 != 0 || src.y2 != 2 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
+			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 1:2 scaling */
+	drm_rect_init(&src, 0, 0, 1 << 16, 1 << 16);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 0, 0, 2, 2);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
+			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 2 ||
+			       dst.y1 != 0 || dst.y2 != 2, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+}
+
+static void igt_drm_rect_clip_scaled_clipped(struct kunit *test)
+{
+	struct drm_rect src, dst, clip;
+	bool visible;
+
+	/* 1:1 scaling top/left clip */
+	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 0, 0, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
+			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 ||
+			       dst.y1 != 0 || dst.y2 != 1, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 1:1 scaling bottom/right clip */
+	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 1, 1, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
+			       src.y1 != 1 << 16 || src.y2 != 2 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 1 || dst.x2 != 2 || dst.y1 != 1 ||
+			       dst.y2 != 2, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 2:1 scaling top/left clip */
+	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 0, 0, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 2 << 16 ||
+			       src.y1 != 0 || src.y2 != 2 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 1 || dst.y1 != 0 ||
+			       dst.y2 != 1, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 2:1 scaling bottom/right clip */
+	drm_rect_init(&src, 0, 0, 4 << 16, 4 << 16);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 1, 1, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 2 << 16 || src.x2 != 4 << 16 ||
+			       src.y1 != 2 << 16 || src.y2 != 4 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 1 || dst.x2 != 2 || dst.y1 != 1 ||
+			       dst.y2 != 2, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 1:2 scaling top/left clip */
+	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
+	drm_rect_init(&dst, 0, 0, 4, 4);
+	drm_rect_init(&clip, 0, 0, 2, 2);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 0 || src.x2 != 1 << 16 ||
+			       src.y1 != 0 || src.y2 != 1 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 0 || dst.x2 != 2 || dst.y1 != 0 ||
+			       dst.y2 != 2, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+
+	/* 1:2 scaling bottom/right clip */
+	drm_rect_init(&src, 0, 0, 2 << 16, 2 << 16);
+	drm_rect_init(&dst, 0, 0, 4, 4);
+	drm_rect_init(&clip, 2, 2, 2, 2);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, src.x1 != 1 << 16 || src.x2 != 2 << 16 ||
+			       src.y1 != 1 << 16 || src.y2 != 2 << 16, "Source badly clipped\n");
+	KUNIT_EXPECT_FALSE_MSG(test, dst.x1 != 2 || dst.x2 != 4 || dst.y1 != 2 ||
+			       dst.y2 != 4, "Destination badly clipped\n");
+	KUNIT_EXPECT_TRUE_MSG(test, visible, "Destination should be visible\n");
+	KUNIT_EXPECT_TRUE_MSG(test, drm_rect_visible(&src), "Source should be visible\n");
+}
+
+static void igt_drm_rect_clip_scaled_signed_vs_unsigned(struct kunit *test)
+{
+	struct drm_rect src, dst, clip;
+	bool visible;
+
+	/*
+	 * 'clip.x2 - dst.x1 >= dst width' could result a negative
+	 * src rectangle width which is no longer expected by the
+	 * code as it's using unsigned types. This could lead to
+	 * the clipped source rectangle appering visible when it
+	 * should have been fully clipped. Make sure both rectangles
+	 * end up invisible.
+	 */
+	drm_rect_init(&src, 0, 0, INT_MAX, INT_MAX);
+	drm_rect_init(&dst, 0, 0, 2, 2);
+	drm_rect_init(&clip, 3, 3, 1, 1);
+
+	visible = drm_rect_clip_scaled(&src, &dst, &clip);
+
+	KUNIT_EXPECT_FALSE_MSG(test, visible, "Destination should not be visible\n");
+	KUNIT_EXPECT_FALSE_MSG(test, drm_rect_visible(&src), "Source should not be visible\n");
+}
+
+static struct kunit_case drm_rect_tests[] = {
+	KUNIT_CASE(igt_drm_rect_clip_scaled_div_by_zero),
+	KUNIT_CASE(igt_drm_rect_clip_scaled_not_clipped),
+	KUNIT_CASE(igt_drm_rect_clip_scaled_clipped),
+	KUNIT_CASE(igt_drm_rect_clip_scaled_signed_vs_unsigned),
+	{ }
+};
+
+static struct kunit_suite drm_rect_test_suite = {
+	.name = "drm_rect",
+	.test_cases = drm_rect_tests,
+};
+
+kunit_test_suite(drm_rect_test_suite);
+
+MODULE_LICENSE("GPL");
-- 
2.35.3