[igt-dev] [PATCH i-g-t] tests/kms_plane_alpha_blend: Dont commit primary for 6bpc display in coverage-vs-premult-vs-none

[Vidya Srinivas]

Intel Gen11 6bpc panels are giving CRC mismatch in coverage-vs-premult-vs-none
if primary gray fb is commited before starting alpha tests. Patch removes primar plane
commit if device is intel and 6bpc.

Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
---
 tests/kms_plane_alpha_blend.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/tests/kms_plane_alpha_blend.c b/tests/kms_plane_alpha_blend.c
index a37cb27c7d62..5f0a8cb070dd 100644
--- a/tests/kms_plane_alpha_blend.c
+++ b/tests/kms_plane_alpha_blend.c
@@ -25,6 +25,7 @@
  */
 
 #include "igt.h"
+#include <string.h>
 
 IGT_TEST_DESCRIPTION("Test plane alpha and blending mode properties");
 
@@ -442,14 +443,45 @@ static void coverage_7efc(data_t *data, enum pipe pipe, igt_plane_t *plane)
 	igt_pipe_crc_stop(data->pipe_crc);
 }
 
+static bool is_6bpc(igt_display_t *display)
+{
+	char buf[4096];
+	char *str;
+	bool ret;
+	int debugfs_fd;
+
+	if (!is_i915_device(display->drm_fd))
+		return false;
+
+	debugfs_fd = igt_debugfs_dir(display->drm_fd);
+
+	if (debugfs_fd < 0)
+		return false;
+
+	igt_debugfs_simple_read(debugfs_fd, "i915_display_info", buf, sizeof(buf));
+
+	str = strstr(buf, "bpp=");
+	if (strncmp(str, "bpp=18", 6) == 0)
+		ret = true;
+	else
+		ret = false;
+
+	close(debugfs_fd);
+	return ret;
+}
+
 static void coverage_premult_constant(data_t *data, enum pipe pipe, igt_plane_t *plane)
 {
 	igt_display_t *display = &data->display;
 	igt_crc_t ref_crc = {}, crc = {};
 
+
 	/* Set a background color on the primary fb for testing */
-	if (plane->type != DRM_PLANE_TYPE_PRIMARY)
-		igt_plane_set_fb(igt_pipe_get_plane_type(&display->pipes[pipe], DRM_PLANE_TYPE_PRIMARY), &data->gray_fb);
+	if (plane->type != DRM_PLANE_TYPE_PRIMARY) {
+		if (!is_6bpc(display))
+			igt_plane_set_fb(igt_pipe_get_plane_type(&display->pipes[pipe],
+						DRM_PLANE_TYPE_PRIMARY), &data->gray_fb);
+	}
 
 	igt_plane_set_prop_enum(plane, IGT_PLANE_PIXEL_BLEND_MODE, "Coverage");
 	igt_plane_set_fb(plane, &data->argb_fb_cov_7e);
-- 
2.7.4