linux-kernel - [PATCH] drm/edid: Support type 7 timings

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Message-Id: <20220118215956.17229-1-iam@lach.pw>
Date:   Wed, 19 Jan 2022 00:59:56 +0300
From:   Yaroslav Bolyukin <iam@...h.pw>
To:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Cc:     Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...ux.ie>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <mripard@...nel.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Yaroslav Bolyukin <iam@...h.pw>
Subject: [PATCH] drm/edid: Support type 7 timings

Per VESA DisplayID Standard v2.0: Type VII Timing – Detailed Timing Data

Definitions were already provided as type I, but not used

Signed-off-by: Yaroslav Bolyukin <iam@...h.pw>
---
 drivers/gpu/drm/drm_edid.c  | 26 +++++++++++++++++---------
 include/drm/drm_displayid.h |  6 +++---
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 12893e7be..5fcefd9b5 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -5404,13 +5404,17 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
 	return quirks;
 }
 
-static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *dev,
-							    struct displayid_detailed_timings_1 *timings)
+static struct drm_display_mode *drm_mode_displayid_detailed_1_7(struct drm_device *dev,
+								struct displayid_detailed_timings_1_7 *timings,
+								bool type_7)
 {
 	struct drm_display_mode *mode;
 	unsigned pixel_clock = (timings->pixel_clock[0] |
 				(timings->pixel_clock[1] << 8) |
 				(timings->pixel_clock[2] << 16)) + 1;
+	// type 7 allows higher precision pixel clock
+	if (!type_7)
+		pixel_clock *= 10;
 	unsigned hactive = (timings->hactive[0] | timings->hactive[1] << 8) + 1;
 	unsigned hblank = (timings->hblank[0] | timings->hblank[1] << 8) + 1;
 	unsigned hsync = (timings->hsync[0] | (timings->hsync[1] & 0x7f) << 8) + 1;
@@ -5426,7 +5430,7 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d
 	if (!mode)
 		return NULL;
 
-	mode->clock = pixel_clock * 10;
+	mode->clock = pixel_clock;
 	mode->hdisplay = hactive;
 	mode->hsync_start = mode->hdisplay + hsync;
 	mode->hsync_end = mode->hsync_start + hsync_width;
@@ -5449,10 +5453,12 @@ static struct drm_display_mode *drm_mode_displayid_detailed(struct drm_device *d
 	return mode;
 }
 
-static int add_displayid_detailed_1_modes(struct drm_connector *connector,
-					  const struct displayid_block *block)
+static int add_displayid_detailed_1_7_modes(struct drm_connector *connector,
+					    const struct displayid_block *block,
+					    bool type_7)
 {
-	struct displayid_detailed_timing_block *det = (struct displayid_detailed_timing_block *)block;
+	struct displayid_detailed_timing_1_7_block *det =
+		(struct displayid_detailed_timing_1_7_block *)block;
 	int i;
 	int num_timings;
 	struct drm_display_mode *newmode;
@@ -5463,9 +5469,9 @@ static int add_displayid_detailed_1_modes(struct drm_connector *connector,
 
 	num_timings = block->num_bytes / 20;
 	for (i = 0; i < num_timings; i++) {
-		struct displayid_detailed_timings_1 *timings = &det->timings[i];
+		struct displayid_detailed_timings_1_7 *timings = &det->timings[i];
 
-		newmode = drm_mode_displayid_detailed(connector->dev, timings);
+		newmode = drm_mode_displayid_detailed_1_7(connector->dev, timings, type_7);
 		if (!newmode)
 			continue;
 
@@ -5485,7 +5491,9 @@ static int add_displayid_detailed_modes(struct drm_connector *connector,
 	displayid_iter_edid_begin(edid, &iter);
 	displayid_iter_for_each(block, &iter) {
 		if (block->tag == DATA_BLOCK_TYPE_1_DETAILED_TIMING)
-			num_modes += add_displayid_detailed_1_modes(connector, block);
+			num_modes += add_displayid_detailed_1_7_modes(connector, block, false);
+		else if (block->tag == DATA_BLOCK_2_TYPE_7_DETAILED_TIMING)
+			num_modes += add_displayid_detailed_1_7_modes(connector, block, true);
 	}
 	displayid_iter_end(&iter);
 
diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h
index 7ffbd9f7b..268ff5e1f 100644
--- a/include/drm/drm_displayid.h
+++ b/include/drm/drm_displayid.h
@@ -111,7 +111,7 @@ struct displayid_tiled_block {
 	u8 topology_id[8];
 } __packed;
 
-struct displayid_detailed_timings_1 {
+struct displayid_detailed_timings_1_7 {
 	u8 pixel_clock[3];
 	u8 flags;
 	u8 hactive[2];
@@ -124,9 +124,9 @@ struct displayid_detailed_timings_1 {
 	u8 vsw[2];
 } __packed;
 
-struct displayid_detailed_timing_block {
+struct displayid_detailed_timing_1_7_block {
 	struct displayid_block base;
-	struct displayid_detailed_timings_1 timings[];
+	struct displayid_detailed_timings_1_7 timings[];
 };
 
 #define DISPLAYID_VESA_MSO_OVERLAP	GENMASK(3, 0)

base-commit: 99613159ad749543621da8238acf1a122880144e
-- 
2.34.1