From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spencer Bull <spencer.bull@dell.com>
Date: Mon, 30 Mar 2026 23:30:00 +0000
Subject: [PATCH] drm/edid: populate monitor range from DisplayID adaptive sync

Some eDP OLED panels advertise a VRR range only via the DisplayID 2.x
Adaptive Sync data block. In that case `display_info.monitor_range`
stays at 0/0 because DRM currently only fills it from the legacy EDID
monitor range descriptor.

Intel's VRR capability path consumes `display_info.monitor_range`
directly, so the connector ends up with `vrr_capable=0` despite EDID
advertising Adaptive Sync.

Backfill `monitor_range` from the DisplayID 2.x Adaptive Sync data
block when the legacy descriptor did not provide a range.
---
diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h
index 5b1b32f..b9b5320 100644
--- a/drivers/gpu/drm/drm_displayid_internal.h
+++ b/drivers/gpu/drm/drm_displayid_internal.h
@@ -67,6 +67,7 @@ struct drm_edid;
 #define DATA_BLOCK_2_TILED_DISPLAY_TOPOLOGY	0x28
 #define DATA_BLOCK_2_CONTAINER_ID		0x29
 #define DATA_BLOCK_2_TYPE_10_FORMULA_TIMING	0x2a
+#define DATA_BLOCK_2_ADAPTIVE_SYNC		0x2b
 #define DATA_BLOCK_2_VENDOR_SPECIFIC		0x7e
 #define DATA_BLOCK_2_CTA_DISPLAY_ID		0x81
 
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index ff432ac..f83e445 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -6527,6 +6527,46 @@ static void drm_get_monitor_range(struct drm_connector *connector,
 		    info->monitor_range.min_vfreq, info->monitor_range.max_vfreq);
 }
 
+#define DISPLAYID_ADAPTIVE_SYNC_DESC_SIZE 6
+
+static void drm_update_displayid_adaptive_sync_range(struct drm_connector *connector,
+					     const struct displayid_block *block)
+{
+	struct drm_monitor_range_info *range = &connector->display_info.monitor_range;
+	const u8 *data = (const u8 *)(block + 1);
+	u16 best_min = 0, best_max = 0;
+	unsigned int best_span = 0;
+	int i;
+
+	if (block->rev != 0 || block->num_bytes < DISPLAYID_ADAPTIVE_SYNC_DESC_SIZE ||
+	    block->num_bytes % DISPLAYID_ADAPTIVE_SYNC_DESC_SIZE)
+		return;
+
+	for (i = 0; i < block->num_bytes; i += DISPLAYID_ADAPTIVE_SYNC_DESC_SIZE) {
+		const u8 *desc = &data[i];
+		u16 min_vfreq = desc[2];
+		u16 max_vfreq = ((((u16)desc[4]) & 0x3) << 8) | desc[3];
+		unsigned int span;
+
+		max_vfreq += 1;
+		if (!min_vfreq || max_vfreq <= min_vfreq)
+			continue;
+
+		span = max_vfreq - min_vfreq;
+		if (span <= best_span)
+			continue;
+
+		best_min = min_vfreq;
+		best_max = max_vfreq;
+		best_span = span;
+	}
+
+	if (best_span) {
+		range->min_vfreq = best_min;
+		range->max_vfreq = best_max;
+	}
+}
+
 static void drm_parse_vesa_mso_data(struct drm_connector *connector,
 				    const struct displayid_block *block)
 {
@@ -6648,26 +6688,41 @@ static void update_displayid_info(struct drm_connector *connector,
 {
 	struct drm_display_info *info = &connector->display_info;
 	const struct displayid_block *block;
+	bool displayid_base_logged = false;
 	struct displayid_iter iter;
 
 	displayid_iter_edid_begin(drm_edid, &iter);
 	displayid_iter_for_each(block, &iter) {
-		drm_dbg_kms(connector->dev,
-			    "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n",
-			    connector->base.id, connector->name,
-			    displayid_version(&iter),
-			    displayid_primary_use(&iter));
-		if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 &&
-		    (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR ||
-		     displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR))
-			info->non_desktop = true;
-
 		/*
-		 * We're only interested in the base section here, no need to
-		 * iterate further.
+		 * Primary use is a DisplayID base section property, but later
+		 * blocks may still carry useful metadata like adaptive sync ranges.
 		 */
-		break;
+		if (!displayid_base_logged) {
+			drm_dbg_kms(connector->dev,
+				    "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n",
+				    connector->base.id, connector->name,
+				    displayid_version(&iter),
+				    displayid_primary_use(&iter));
+			if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 &&
+			    (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR ||
+			     displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR))
+				info->non_desktop = true;
+
+			displayid_base_logged = true;
+		}
+
+		if (!info->monitor_range.min_vfreq && !info->monitor_range.max_vfreq &&
+		    block->tag == DATA_BLOCK_2_ADAPTIVE_SYNC)
+			drm_update_displayid_adaptive_sync_range(connector, block);
 	}
+
+	if (info->monitor_range.min_vfreq && info->monitor_range.max_vfreq)
+		drm_dbg_kms(connector->dev,
+			    "[CONNECTOR:%d:%s] DisplayID adaptive sync refresh rate range is %d Hz - %d Hz\n",
+			    connector->base.id, connector->name,
+			    info->monitor_range.min_vfreq,
+			    info->monitor_range.max_vfreq);
+
 	displayid_iter_end(&iter);
 }