edid: parse timing data from CVT range limit descriptor

Signed-off-by: Simon Ser <contact@emersion.fr>

di-edid-decode.c

@@ -341,6 +341,24 @@ display_range_limits_type_name(enum di_edid_display_range_limits_type type)
 	abort();
 }
 
+static const char *
+cvt_aspect_ratio_name(enum di_edid_cvt_aspect_ratio aspect_ratio)
+{
+	switch (aspect_ratio) {
+	case DI_EDID_CVT_ASPECT_RATIO_4_3:
+		return "4:3";
+	case DI_EDID_CVT_ASPECT_RATIO_16_9:
+		return "16:9";
+	case DI_EDID_CVT_ASPECT_RATIO_16_10:
+		return "16:10";
+	case DI_EDID_CVT_ASPECT_RATIO_5_4:
+		return "5:4";
+	case DI_EDID_CVT_ASPECT_RATIO_15_9:
+		return "15:9";
+	}
+	abort();
+}
+
 static void
 print_display_desc(const struct di_edid *edid,
 		   const struct di_edid_display_descriptor *desc)
@@ -397,6 +415,51 @@ print_display_desc(const struct di_edid *edid,
 			printf("        K: %u\n", (int) range_limits->secondary_gtf->k);
 			printf("        J: %.1f%%\n", range_limits->secondary_gtf->j);
 			break;
+		case DI_EDID_DISPLAY_RANGE_LIMITS_CVT:
+			printf("      CVT version %d.%d\n",
+			       range_limits->cvt->version,
+			       range_limits->cvt->revision);
+
+			if (range_limits->cvt->max_horiz_px != 0)
+				printf("      Max active pixels per line: %d\n",
+				       range_limits->cvt->max_horiz_px);
+
+			printf("      Supported aspect ratios:");
+			if (range_limits->cvt->supported_aspect_ratio & DI_EDID_CVT_ASPECT_RATIO_4_3)
+				printf(" 4:3");
+			if (range_limits->cvt->supported_aspect_ratio & DI_EDID_CVT_ASPECT_RATIO_16_9)
+				printf(" 16:9");
+			if (range_limits->cvt->supported_aspect_ratio & DI_EDID_CVT_ASPECT_RATIO_16_10)
+				printf(" 16:10");
+			if (range_limits->cvt->supported_aspect_ratio & DI_EDID_CVT_ASPECT_RATIO_5_4)
+				printf(" 5:4");
+			if (range_limits->cvt->supported_aspect_ratio & DI_EDID_CVT_ASPECT_RATIO_15_9)
+				printf(" 15:9");
+			printf("\n");
+
+			printf("      Preferred aspect ratio: %s\n",
+			       cvt_aspect_ratio_name(range_limits->cvt->preferred_aspect_ratio));
+
+			if (range_limits->cvt->standard_blanking)
+				printf("      Supports CVT standard blanking\n");
+			if (range_limits->cvt->reduced_blanking)
+				printf("      Supports CVT reduced blanking\n");
+
+			if (range_limits->cvt->supported_scaling != 0) {
+				printf("      Supported display scaling:\n");
+				if (range_limits->cvt->supported_scaling & DI_EDID_CVT_SCALING_HORIZ_SHRINK)
+					printf("        Horizontal shrink\n");
+				if (range_limits->cvt->supported_scaling & DI_EDID_CVT_SCALING_HORIZ_STRETCH)
+					printf("        Horizontal stretch\n");
+				if (range_limits->cvt->supported_scaling & DI_EDID_CVT_SCALING_VERT_SHRINK)
+					printf("        Vertical shrink\n");
+				if (range_limits->cvt->supported_scaling & DI_EDID_CVT_SCALING_VERT_STRETCH)
+					printf("        Vertical stretch\n");
+			}
+
+			printf("      Preferred vertical refresh: %d Hz\n",
+			       range_limits->cvt->preferred_vert_refresh_hz);
+			break;
 		default:
 			break;
 		}

edid.c

@@ -496,12 +496,13 @@ parse_display_range_limits(struct di_edid *edid,
 			   struct di_edid_display_range_limits_priv *priv)
 {
 	uint8_t offset_flags, vert_offset_flags, horiz_offset_flags;
-	uint8_t support_flags;
+	uint8_t support_flags, preferred_aspect_ratio;
 	int max_vert_offset = 0, min_vert_offset = 0;
 	int max_horiz_offset = 0, min_horiz_offset = 0;
 	size_t i;
 	struct di_edid_display_range_limits *base;
 	struct di_edid_display_range_limits_secondary_gtf *secondary_gtf;
+	struct di_edid_display_range_limits_cvt *cvt;
 
 	base = &priv->base;
 
@@ -633,7 +634,64 @@ parse_display_range_limits(struct di_edid *edid,
 		base->secondary_gtf = secondary_gtf;
 		break;
 	case DI_EDID_DISPLAY_RANGE_LIMITS_CVT:
-		/* TODO: parse video timing data in bytes 11 to 17 */
+		cvt = &priv->cvt;
+
+		cvt->version = get_bit_range(data[11], 7, 4);
+		cvt->revision = get_bit_range(data[11], 3, 0);
+
+		base->max_pixel_clock_hz -= get_bit_range(data[12], 7, 2) * 250 * 1000;
+		cvt->max_horiz_px = 8 * ((get_bit_range(data[12], 1, 0) << 8) | data[13]);
+
+		cvt->supported_aspect_ratio = data[14];
+		if (get_bit_range(data[14], 2, 0) != 0)
+			add_failure_until(edid, 4,
+					  "Display Range Limits: Reserved bits of byte 14 are non-zero.");
+
+		preferred_aspect_ratio = get_bit_range(data[15], 7, 5);
+		switch (preferred_aspect_ratio) {
+		case 0:
+			cvt->preferred_aspect_ratio = DI_EDID_CVT_ASPECT_RATIO_4_3;
+			break;
+		case 1:
+			cvt->preferred_aspect_ratio = DI_EDID_CVT_ASPECT_RATIO_16_9;
+			break;
+		case 2:
+			cvt->preferred_aspect_ratio = DI_EDID_CVT_ASPECT_RATIO_16_10;
+			break;
+		case 3:
+			cvt->preferred_aspect_ratio = DI_EDID_CVT_ASPECT_RATIO_5_4;
+			break;
+		case 4:
+			cvt->preferred_aspect_ratio = DI_EDID_CVT_ASPECT_RATIO_15_9;
+			break;
+		default:
+			/* Reserved */
+			add_failure_until(edid, 4,
+					  "Display Range Limits: Invalid preferred aspect ratio 0x%02x.",
+					  preferred_aspect_ratio);
+			return false;
+		}
+
+		cvt->standard_blanking = has_bit(data[15], 3);
+		cvt->reduced_blanking = has_bit(data[15], 4);
+
+		if (get_bit_range(data[15], 2, 0) != 0)
+			add_failure_until(edid, 4,
+					  "Display Range Limits: Reserved bits of byte 15 are non-zero.");
+
+		cvt->supported_scaling = data[16];
+		if (get_bit_range(data[16], 3, 0) != 0)
+			add_failure_until(edid, 4,
+					  "Display Range Limits: Reserved bits of byte 16 are non-zero.");
+
+		cvt->preferred_vert_refresh_hz = data[17];
+		if (cvt->preferred_vert_refresh_hz == 0) {
+			add_failure_until(edid, 4,
+					  "Display Range Limits: Preferred vertical refresh rate must be specified.");
+			return false;
+		}
+
+		base->cvt = cvt;
 		break;
 	case DI_EDID_DISPLAY_RANGE_LIMITS_BARE:
 	case DI_EDID_DISPLAY_RANGE_LIMITS_DEFAULT_GTF:

include/edid.h

@@ -84,6 +84,7 @@ struct di_edid {
 struct di_edid_display_range_limits_priv {
 	struct di_edid_display_range_limits base;
 	struct di_edid_display_range_limits_secondary_gtf secondary_gtf;
+	struct di_edid_display_range_limits_cvt cvt;
 };
 
 struct di_edid_display_descriptor {

include/libdisplay-info/edid.h

@@ -558,6 +558,40 @@ struct di_edid_display_range_limits_secondary_gtf {
 	float c, m, k, j;
 };
 
+enum di_edid_cvt_aspect_ratio {
+	DI_EDID_CVT_ASPECT_RATIO_4_3 = 1 << 7,
+	DI_EDID_CVT_ASPECT_RATIO_16_9 = 1 << 6,
+	DI_EDID_CVT_ASPECT_RATIO_16_10 = 1 << 5,
+	DI_EDID_CVT_ASPECT_RATIO_5_4 = 1 << 4,
+	DI_EDID_CVT_ASPECT_RATIO_15_9 = 1 << 3,
+};
+
+enum di_edid_cvt_scaling {
+	DI_EDID_CVT_SCALING_HORIZ_SHRINK = 1 << 7,
+	DI_EDID_CVT_SCALING_HORIZ_STRETCH = 1 << 6,
+	DI_EDID_CVT_SCALING_VERT_SHRINK = 1 << 5,
+	DI_EDID_CVT_SCALING_VERT_STRETCH = 1 << 4,
+};
+
+struct di_edid_display_range_limits_cvt {
+	int32_t version, revision;
+	/* Maximum active pixels per line, zero for no limit */
+	int32_t max_horiz_px;
+	/* Supported aspect ratio, bitfield of enum di_edid_cvt_aspect_ratio */
+	uint32_t supported_aspect_ratio;
+	/* Preferred aspect ratio */
+	enum di_edid_cvt_aspect_ratio preferred_aspect_ratio;
+	/* Whether standard CVT blanking is supported */
+	bool standard_blanking;
+	/* Whether reduced CVT blanking is supported */
+	bool reduced_blanking;
+	/* Supported types of display scaling, bitfield of
+	 * enum di_edid_cvt_scaling */
+	uint32_t supported_scaling;
+	/* Preferred vertical refresh rate, in Hz */
+	int32_t preferred_vert_refresh_hz;
+};
+
 /**
  * EDID display range limits, defined in section 3.10.3.3.1.
  */
@@ -569,13 +603,16 @@ struct di_edid_display_range_limits {
 	int32_t min_horiz_rate_hz, max_horiz_rate_hz;
 
 	/* Maximum pixel clock in Hz, zero if unset, rounded to the nearest
-	 * multiple of 10 MHz */
+	 * multiple of 0.25 MHz if CVT, otherwise to the nearest multiple of
+	 * 10 MHz */
 	int32_t max_pixel_clock_hz;
 
 	enum di_edid_display_range_limits_type type;
 
 	/* For SECONDARY_GTF limits, NULL otherwise */
 	const struct di_edid_display_range_limits_secondary_gtf *secondary_gtf;
+	/* For CVT limits, NULL otherwise */
+	const struct di_edid_display_range_limits_cvt *cvt;
 };
 
 /**

test/data/viewsonic-vp2768-dp.diff

@@ -23,26 +23,7 @@
    Detailed Timing Descriptors:
      DTD 1:  2560x1440   59.950550 Hz  16:9     88.787 kHz    241.500000 MHz (597 mm x 336 mm)
                   Hfront   48 Hsync  32 Hback   80 Hpol P
-@@ -53,18 +53,6 @@
+@@ -79,35 +79,29 @@
-     Display Product Serial Number: 'UY5171500307'
-     Display Range Limits:
-       Monitor ranges (CVT): 50-75 Hz V, 24-90 kHz H, max dotclock 250 MHz
--      CVT version 1.1
--      Max active pixels per line: 6400
--      Supported aspect ratios: 4:3 16:9
--      Preferred aspect ratio: 16:9
--      Supports CVT standard blanking
--      Supports CVT reduced blanking
--      Supported display scaling:
--        Horizontal shrink
--        Horizontal stretch
--        Vertical shrink
--        Vertical stretch
--      Preferred vertical refresh: 60 Hz
-     Display Product Name: 'VP2768 Series'
-   Extension blocks: 1
- Checksum: 0xa0
-@@ -79,35 +67,29 @@
    Supports YCbCr 4:2:2
    Native detailed modes: 1
    Video Data Block:
@@ -94,7 +75,7 @@
      DTD 4:  1280x720    60.000000 Hz  16:9     45.000 kHz     74.250000 MHz (597 mm x 336 mm)
                   Hfront  110 Hsync  40 Hback  220 Hpol P
                   Vfront    5 Vsync   5 Vback   20 Vpol P
-@@ -117,28 +99,8 @@
+@@ -117,28 +111,14 @@
      DTD 6:  1920x1080   50.000000 Hz  16:9     56.250 kHz    148.500000 MHz (597 mm x 336 mm)
                   Hfront  528 Hsync  44 Hback  148 Hpol P
                   Vfront    4 Vsync   5 Vback   36 Vpol P
@@ -111,17 +92,16 @@
 -  Base EDID: Some timings are out of range of the Monitor Ranges:
 -    Vertical Freq: 24.000 - 75.062 Hz (Monitor: 50.000 - 75.000 Hz)
 -
--Failures:
+ Failures:
--
+ 
--Block 0, Base EDID:
+ Block 0, Base EDID:
 -  Basic Display Parameters & Features: sRGB is signaled, but the chromaticities do not match.
--  Display Range Limits: Reserved bits of byte 14 are non-zero.
+   Display Range Limits: Reserved bits of byte 14 are non-zero.
--  Display Range Limits: Reserved bits of byte 15 are non-zero.
+   Display Range Limits: Reserved bits of byte 15 are non-zero.
--  Display Range Limits: Reserved bits of byte 16 are non-zero.
+   Display Range Limits: Reserved bits of byte 16 are non-zero.
 -Block 1, CTA-861 Extension Block:
 -  Missing VCDB, needed for Set Selectable RGB Quantization to avoid interop issues.
 -EDID:
 -  CTA-861: Native progressive timings are a mix of several resolutions.
 -
--EDID conformity: FAIL
+ EDID conformity: FAIL
-+EDID conformity: PASS