[v5 i-g-t 1/3] tests/kms_color_helper: Read deep-color capability from EDID

[Bhanuprakash Modem]

Add a helper function to read the panel's deep-color capability
from EDID.

First search for Vendor Specific Data Block
-----------------------------------------------------------------
  Bit field |              Description
-----------------------------------------------------------------
  Bit 7    |  A function that needs info from ACP or ISRC packets
  Bit 6    |  16-bit-per-channel deep color (48-bit)
  Bit 5    |  12-bit-per-channel deep color (36-bit)
  Bit 4    |  10-bit-per-channel deep color (30-bit)
  Bit 3    |  4:4:4 in deep color modes
  Bit 2    |  Reserved, 0
  Bit 1    |  Reserved, 0
  Bit 0    |  DVI Dual Link Operation
-----------------------------------------------------------------
Then fallback to the Video Signal Interface if VSDB not found

https://glenwing.github.io/docs/VESA-EEDID-A2.pdf
(3.6.1 Video Input Definition: 1 Byte)

-----------------------------------------------------------------
| 7 | 6 5 4 3 2 1 0 | Video Signal Interface: Bit 7             |
|---|---------------|-------------------------------------------|
| 1 | x x x x x x x | Input is a Digital Video Signal Interface |
-----------------------------------------------------------------

-----------------------------------------------------
| 7 | 6 5 4 | 3 2 1 0 | Color Bit Depth: Bits 6 → 4 |
|---|-------|---------|-----------------------------|
| 1 | 0 0 0 | x x x x | Color Bit Depth is undefined|
| 1 | 0 0 1 | x x x x | 6 Bits per Primary Color    |
| 1 | 0 1 0 | x x x x | 8 Bits per Primary Color    |
| 1 | 0 1 1 | x x x x | 10 Bits per Primary Color   |
| 1 | 1 0 0 | x x x x | 12 Bits per Primary Color   |
| 1 | 1 0 1 | x x x x | 14 Bits per Primary Color   |
| 1 | 1 1 0 | x x x x | 16 Bits per Primary Color   |
| 1 | 1 1 1 | x x x x | Reserved (Do Not Use)       |
|---|-------|---------|-----------------------------|

For deep-color we need atleast 10-bits.

Cc: Uma Shankar <uma.shankar at intel.com>
Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
---
 tests/kms_color_helper.c | 92 ++++++++++++++++++++++++++++++++++++++++
 tests/kms_color_helper.h |  3 ++
 2 files changed, 95 insertions(+)

diff --git a/tests/kms_color_helper.c b/tests/kms_color_helper.c
index d71e7bb2e6..9234b616ac 100644
--- a/tests/kms_color_helper.c
+++ b/tests/kms_color_helper.c
@@ -24,6 +24,98 @@
 
 #include "kms_color_helper.h"
 
+bool
+is_panel_supports_deep_color(int fd, drmModeConnector *connector)
+{
+	uint64_t edid_blob_id;
+	const struct edid *edid;
+	uint8_t bit_depth;
+	struct edid_cea_data_block *vsdb;
+	uint8_t flags1 = 0;
+	int i;
+	drmModePropertyBlobPtr edid_blob = NULL;
+
+	igt_assert(kmstest_get_property(fd, connector->connector_id,
+					DRM_MODE_OBJECT_CONNECTOR, "EDID", NULL,
+					&edid_blob_id, NULL));
+	igt_assert(edid_blob = drmModeGetPropertyBlob(fd, edid_blob_id));
+
+	edid = (const struct edid *) edid_blob->data;
+
+	/* First search for Vendor Specific Data Block
+	 * -----------------------------------------------------------------
+	 * Bit field |              Description
+	 * -----------------------------------------------------------------
+	 *  Bit 7    |  A function that needs info from ACP or ISRC packets
+	 *  Bit 6    |  16-bit-per-channel deep color (48-bit)
+	 *  Bit 5    |  12-bit-per-channel deep color (36-bit)
+	 *  Bit 4    |  10-bit-per-channel deep color (30-bit)
+	 *  Bit 3    |  4:4:4 in deep color modes
+	 *  Bit 2    |  Reserved, 0
+	 *  Bit 1    |  Reserved, 0
+	 *  Bit 0    |  DVI Dual Link Operation
+	 * -----------------------------------------------------------------
+	 */
+	for (i = 0; i < edid->extensions_len; i++) {
+		vsdb = (struct edid_cea_data_block *) edid->extensions[0].data.cea.data;
+
+		if (vsdb->type_len != EDID_CEA_DATA_VENDOR_SPECIFIC)
+			continue;
+
+		flags1 = (vsdb->data.vsdbs[0].data.hdmi.flags1) & (7 << 6);
+		drmModeFreePropertyBlob(edid_blob);
+
+		if (flags1)
+			return true;
+		else
+			return false;
+	}
+
+	bit_depth = edid->input;
+	drmModeFreePropertyBlob(edid_blob);
+
+	/*
+	 * If VSDB is not found then fallback to Video Signal Interface
+	 *
+	 * https://glenwing.github.io/docs/VESA-EEDID-A2.pdf
+	 * (3.6.1 Video Input Definition: 1 Byte)
+	 *
+	 * -----------------------------------------------------------------
+	 * | 7 | 6 5 4 3 2 1 0 | Video Signal Interface: Bit 7             |
+	 * |---|---------------|-------------------------------------------|
+	 * | 1 | x x x x x x x | Input is a Digital Video Signal Interface |
+	 * -----------------------------------------------------------------
+	 *
+	 * -----------------------------------------------------
+	 * | 7 | 6 5 4 | 3 2 1 0 | Color Bit Depth: Bits 6 → 4 |
+	 * |---|-------|---------|-----------------------------|
+	 * | 1 | 0 0 0 | x x x x | Color Bit Depth is undefined|
+	 * | 1 | 0 0 1 | x x x x | 6 Bits per Primary Color    |
+	 * | 1 | 0 1 0 | x x x x | 8 Bits per Primary Color    |
+	 * | 1 | 0 1 1 | x x x x | 10 Bits per Primary Color   |
+	 * | 1 | 1 0 0 | x x x x | 12 Bits per Primary Color   |
+	 * | 1 | 1 0 1 | x x x x | 14 Bits per Primary Color   |
+	 * | 1 | 1 1 0 | x x x x | 16 Bits per Primary Color   |
+	 * | 1 | 1 1 1 | x x x x | Reserved (Do Not Use)       |
+	 * -----------------------------------------------------
+	 *
+	 * For deep-color we need atleast 10-bits.
+	 */
+
+	if (!(bit_depth & (1 << 7)))
+		return false;
+	if (((bit_depth & (7 << 4)) >> 4) >= 3)
+		return true;
+
+	return false;
+}
+
+bool is_max_bpc_supported(igt_output_t *output)
+{
+	return igt_output_has_prop(output, IGT_CONNECTOR_MAX_BPC) &&
+		igt_output_get_prop(output, IGT_CONNECTOR_MAX_BPC);
+}
+
 void paint_gradient_rectangles(data_t *data,
 			       drmModeModeInfo *mode,
 			       color_t *colors,
diff --git a/tests/kms_color_helper.h b/tests/kms_color_helper.h
index bb6f0054f3..992087ac9c 100644
--- a/tests/kms_color_helper.h
+++ b/tests/kms_color_helper.h
@@ -36,6 +36,7 @@
 #include "drm.h"
 #include "drmtest.h"
 #include "igt.h"
+#include "igt_edid.h"
 
 
 /* Internal */
@@ -64,6 +65,8 @@ typedef struct {
 	color_t coeffs[];
 } gamma_lut_t;
 
+bool is_panel_supports_deep_color(int fd, drmModeConnector *connector);
+bool is_max_bpc_supported(igt_output_t *output);
 void paint_gradient_rectangles(data_t *data,
 			       drmModeModeInfo *mode,
 			       color_t *colors,
-- 
2.32.0