[Intel-gfx] [PATCH igt 3/3] kms_frontbuffer_tracking: properly handle mixing GTT and WC mmaps

[Paulo Zanoni]

The new Kernel behavior is that whenever a buffer has ever been WC
mmapped, the GTT mmaps will be treated as CPU operations. Because of
this, if we don't issue the dirty_fb IOCTL after doing frontbuffer
rendering with the GTT mmaps, FBC will remain disabled. Luckily, the
only subtest that does this sort of mix is the multidraw subtest.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 tests/kms_frontbuffer_tracking.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tests/kms_frontbuffer_tracking.c b/tests/kms_frontbuffer_tracking.c
index f37de6d..89e6ea8 100644
--- a/tests/kms_frontbuffer_tracking.c
+++ b/tests/kms_frontbuffer_tracking.c
@@ -2079,6 +2079,7 @@ static void multidraw_subtest(const struct test_mode *t)
 	struct modeset_params *params = pick_params(t);
 	struct fb_region *target;
 	enum igt_draw_method m1, m2, used_method;
+	bool wc_used = false;
 
 	switch (t->plane) {
 	case PLANE_PRI:
@@ -2108,6 +2109,17 @@ static void multidraw_subtest(const struct test_mode *t)
 					igt_draw_get_method_name(used_method));
 
 				draw_rect(pattern, target, used_method, r);
+
+				if (used_method == IGT_DRAW_MMAP_WC)
+					wc_used = true;
+
+				if (used_method == IGT_DRAW_MMAP_GTT &&
+				    wc_used) {
+					struct rect rect =
+						pattern->get_rect(target, r);
+					fb_dirty_ioctl(target, &rect);
+				}
+
 				update_wanted_crc(t,
 						  &pattern->crcs[t->format][r]);
 
-- 
2.8.0.rc3