[igt-dev] [PATCH i-g-t 3/3] tests/kms_plane: Throw away yet another bi

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

CHV pipe A/C sprites are causing a crc mismatch with BT.601
when we keep the six msbs. If we throw away one more bit we get
matches for BT.601. BT.709 matches even with 6 bits, as do the
pipe B planes with their programmable CSC. Also IVB and KBL
were both happy with 6 bits, so doesn't seem that that these
CHV mismatches are due to bugs in our code, just the hw is
a bit imprecise.

Cc: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 tests/kms_plane.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/tests/kms_plane.c b/tests/kms_plane.c
index 13d36254dfe3..e4f3b8d68748 100644
--- a/tests/kms_plane.c
+++ b/tests/kms_plane.c
@@ -30,6 +30,13 @@
 #include <stdio.h>
 #include <string.h>
 
+/*
+ * Throw away enough lsbs in pixel formats tests
+ * to get a match despite some differences between
+ * the software and hardware YCbCr<->RGB conversion
+ * routines.
+ */
+#define LUT_MASK 0xf800
 
 typedef struct {
 	float red;
@@ -690,7 +697,7 @@ static bool test_format_plane(data_t *data, enum pipe pipe,
 			continue;
 
 		if (format == DRM_FORMAT_C8) {
-			if (!set_c8_legacy_lut(data, pipe, 0xfc00))
+			if (!set_c8_legacy_lut(data, pipe, LUT_MASK))
 				continue;
 		} else {
 			if (!igt_fb_supported_format(format))
@@ -709,7 +716,7 @@ static bool test_format_plane(data_t *data, enum pipe pipe,
 							ref_crc, &fb);
 
 		if (format == DRM_FORMAT_C8)
-			set_legacy_lut(data, pipe, 0xfc00);
+			set_legacy_lut(data, pipe, LUT_MASK);
 	}
 
 	igt_pipe_crc_stop(data->pipe_crc);
@@ -744,7 +751,7 @@ test_pixel_formats(data_t *data, enum pipe pipe)
 
 	igt_display_commit2(&data->display, data->display.is_atomic ? COMMIT_ATOMIC : COMMIT_LEGACY);
 
-	set_legacy_lut(data, pipe, 0xfc00);
+	set_legacy_lut(data, pipe, LUT_MASK);
 
 	test_init(data, pipe);
 
-- 
2.21.0