[PATCH 7/7] nouveau: honor HF-EEODB EDIDs by converting to struct drm_edid

HDMI 2.1 sinks ship HF-EEODB EDIDs. Byte 126 deliberately claims one
extension block for legacy sources, and the true count lives in the CTA
block's first data block. Their high-refresh timings (e.g., 4K240, 6K165,
etc) sit in DisplayID extension blocks 2+.

The kernel already reads these EDIDs whole, and on GSP boards RM returns
the full EDID with its true size. However, nouveau then hands the buffer
to the legacy API which sizes the EDID from byte 126 so the DisplayID
blocks are not parsed/exposed and the sysfs blob truncates to 256 bytes.

Convert to the struct drm_edid API, which carries the real size.
Read via drm_edid_read_ddc()/drm_edid_read_switcheroo() where an
adapter exists, and serve RM's buffer through drm_edid_read_custom()
with a block-reading callback where not, which also routes the GSP
path through drm's block validation and the debugfs EDID override
(previously dead on GSP boards, since nothing consulted it outside
the i2c readers).

The connector keeps a borrowed const drm_edid_raw() view in ->edid, same
as i915's detect_edid so the raw-EDID consumers (SAD parsing, deep-color
flags, the DVI dual-link byte, DP CEC) are untouched. Ownership and
freeing move to the drm_edid. The OF path additionally now frees any
previous EDID itself rather than relying on the callers. MST connectors
keep their separate legacy path.

Signed-off-by: Mohamed Ahmed <[email protected]>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c     |  2 +-
 drivers/gpu/drm/nouveau/nouveau_connector.c | 95 ++++++++++++++++-----
 drivers/gpu/drm/nouveau/nouveau_connector.h |  7 +-
 3 files changed, 80 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 364227f5456f..c3b7fd29c077 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1804,7 +1804,7 @@ nv50_sor_atomic_enable(struct drm_encoder *encoder, struct drm_atomic_commit *st
 			lvds_8bpc = bios->fp.if_is_24bit;
 		} else {
 			if (nv_connector->type == DCB_CONNECTOR_LVDS_SPWG) {
-				if (((u8 *)nv_connector->edid)[121] == 2)
+				if (((const u8 *)nv_connector->edid)[121] == 2)
 					lvds_dual = true;
 			} else
 			if (mode->clock >= bios->fp.duallink_transition_clk) {
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.c b/drivers/gpu/drm/nouveau/nouveau_connector.c
index b0b0ad9a0c24..4105555151c9 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.c
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.c
@@ -397,7 +397,7 @@ nouveau_connector_destroy(struct drm_connector *connector)
 	struct nouveau_connector *nv_connector = nouveau_connector(connector);
 	nvif_event_dtor(&nv_connector->irq);
 	nvif_event_dtor(&nv_connector->hpd);
-	kfree(nv_connector->edid);
+	drm_edid_free(nv_connector->drm_edid);
 	drm_connector_unregister(connector);
 	drm_connector_cleanup(connector);
 	if (nv_connector->aux.transfer)
@@ -490,8 +490,11 @@ nouveau_connector_of_detect(struct drm_connector *connector)
 		int idx = name ? name[strlen(name) - 1] - 'A' : 0;
 
 		if (nv_encoder->dcb->i2c_index == idx && edid) {
+			drm_edid_free(nv_connector->drm_edid);
+			nv_connector->drm_edid =
+				drm_edid_alloc(edid, EDID_LENGTH);
 			nv_connector->edid =
-				kmemdup(edid, EDID_LENGTH, GFP_KERNEL);
+				drm_edid_raw(nv_connector->drm_edid);
 			return nv_encoder;
 		}
 	}
@@ -546,17 +549,42 @@ nouveau_connector_set_encoder(struct drm_connector *connector,
 	}
 }
 
+struct nouveau_rm_edid {
+	u8 *data;
+	int size;
+};
+
+static int
+nouveau_connector_rm_edid_block(void *context, u8 *buf, unsigned int block,
+				size_t len)
+{
+	struct nouveau_rm_edid *rm = context;
+	size_t offset = (size_t)block * EDID_LENGTH;
+
+	if (offset + len > rm->size)
+		return -EINVAL;
+
+	memcpy(buf, rm->data + offset, len);
+	return 0;
+}
+
 static void
 nouveau_connector_set_edid(struct nouveau_connector *nv_connector,
-			   struct edid *edid)
+			   const struct drm_edid *drm_edid)
 {
-	if (nv_connector->edid != edid) {
-		struct edid *old_edid = nv_connector->edid;
+	if (nv_connector->drm_edid == drm_edid)
+		return;
 
-		drm_connector_update_edid_property(&nv_connector->base, edid);
-		kfree(old_edid);
-		nv_connector->edid = edid;
-	}
+	/* Updates the EDID property and display_info with HF-EEODB-aware
+	 * sizing. The legacy helpers truncate both to what EDID byte 126
+	 * admits, hiding the DisplayID extension blocks that carry every
+	 * timing a DTD can't express (>655.35 MHz).
+	 */
+	drm_edid_connector_update(&nv_connector->base, drm_edid);
+
+	drm_edid_free(nv_connector->drm_edid);
+	nv_connector->drm_edid = drm_edid;
+	nv_connector->edid = drm_edid_raw(drm_edid);
 }
 
 static enum drm_connector_status
@@ -590,20 +618,36 @@ nouveau_connector_detect(struct drm_connector *connector, bool force)
 
 	nv_encoder = nouveau_connector_ddc_detect(connector);
 	if (nv_encoder) {
-		struct edid *new_edid = NULL;
+		const struct drm_edid *new_edid = NULL;
 
 		if (nv_encoder->i2c) {
 			if ((vga_switcheroo_handler_flags() & VGA_SWITCHEROO_CAN_SWITCH_DDC) &&
 			    nv_connector->type == DCB_CONNECTOR_LVDS)
-				new_edid = drm_get_edid_switcheroo(connector, nv_encoder->i2c);
+				new_edid = drm_edid_read_switcheroo(connector, nv_encoder->i2c);
 			else
-				new_edid = drm_get_edid(connector, nv_encoder->i2c);
+				new_edid = drm_edid_read_ddc(connector, nv_encoder->i2c);
 		} else {
-			ret = nvif_outp_edid_get(&nv_encoder->outp, (u8 **)&new_edid);
+			struct nouveau_rm_edid rm = {};
+
+			ret = nvif_outp_edid_get(&nv_encoder->outp, &rm.data);
 			if (ret < 0)
 				return connector_status_disconnected;
+
+			/* ret is RM's true buffer size: an HF-EEODB EDID is
+			 * larger than its byte 126 admits, and RM (which
+			 * owns the DDC pads on GSP boards) reads it whole.
+			 * Serve it through drm's block reader so EEODB
+			 * sizing, block validation, and the debugfs EDID
+			 * override all apply.
+			 */
+			rm.size = ret;
+			new_edid = drm_edid_read_custom(connector,
+							nouveau_connector_rm_edid_block,
+							&rm);
+			kfree(rm.data);
 		}
 
+
 		nouveau_connector_set_edid(nv_connector, new_edid);
 		if (!nv_connector->edid) {
 			NV_ERROR(drm, "DDC responded, but no EDID for %s\n",
@@ -686,7 +730,7 @@ nouveau_connector_detect_lvds(struct drm_connector *connector, bool force)
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nouveau_connector *nv_connector = nouveau_connector(connector);
 	struct nouveau_encoder *nv_encoder = NULL;
-	struct edid *edid = NULL;
+	const struct drm_edid *edid = NULL;
 	enum drm_connector_status status = connector_status_disconnected;
 
 	nv_encoder = find_encoder(connector, DCB_OUTPUT_LVDS);
@@ -697,7 +741,7 @@ nouveau_connector_detect_lvds(struct drm_connector *connector, bool force)
 	if (!drm->vbios.fp_no_ddc) {
 		status = nouveau_connector_detect(connector, force);
 		if (status == connector_status_connected) {
-			edid = nv_connector->edid;
+			edid = nv_connector->drm_edid;
 			goto out;
 		}
 	}
@@ -712,7 +756,13 @@ nouveau_connector_detect_lvds(struct drm_connector *connector, bool force)
 	 * valid - it's not (rh#613284)
 	 */
 	if (nv_encoder->dcb->lvdsconf.use_acpi_for_edid) {
-		edid = nouveau_acpi_edid(dev, connector);
+		struct edid *raw = nouveau_acpi_edid(dev, connector);
+
+		if (raw) {
+			edid = drm_edid_alloc(raw,
+					      EDID_LENGTH * (1 + raw->extensions));
+			kfree(raw);
+		}
 		if (edid) {
 			status = connector_status_connected;
 			goto out;
@@ -733,9 +783,10 @@ nouveau_connector_detect_lvds(struct drm_connector *connector, bool force)
 	 * stored for the panel stored in them.
 	 */
 	if (!drm->vbios.fp_no_ddc) {
-		edid = (struct edid *)nouveau_bios_embedded_edid(dev);
-		if (edid) {
-			edid = kmemdup(edid, EDID_LENGTH, GFP_KERNEL);
+		const void *embedded = nouveau_bios_embedded_edid(dev);
+
+		if (embedded) {
+			edid = drm_edid_alloc(embedded, EDID_LENGTH);
 			if (edid)
 				status = connector_status_connected;
 		}
@@ -915,7 +966,7 @@ nouveau_connector_detect_depth(struct drm_connector *connector)
 	 */
 	if (nv_connector->edid &&
 	    nv_connector->type == DCB_CONNECTOR_LVDS_SPWG)
-		duallink = ((u8 *)nv_connector->edid)[121] == 2;
+		duallink = ((const u8 *)nv_connector->edid)[121] == 2;
 	else
 		duallink = mode->clock >= bios->fp.duallink_transition_clk;
 
@@ -973,8 +1024,8 @@ nouveau_connector_get_modes(struct drm_connector *connector)
 		nv_connector->native_mode = NULL;
 	}
 
-	if (nv_connector->edid)
-		ret = drm_add_edid_modes(connector, nv_connector->edid);
+	if (nv_connector->drm_edid)
+		ret = drm_edid_connector_add_modes(connector);
 	else
 	if (nv_encoder->dcb->type == DCB_OUTPUT_LVDS &&
 	    (nv_encoder->dcb->lvdsconf.use_straps_for_mode ||
diff --git a/drivers/gpu/drm/nouveau/nouveau_connector.h b/drivers/gpu/drm/nouveau/nouveau_connector.h
index 0608cabed058..ca8f310b3680 100644
--- a/drivers/gpu/drm/nouveau/nouveau_connector.h
+++ b/drivers/gpu/drm/nouveau/nouveau_connector.h
@@ -137,7 +137,12 @@ struct nouveau_connector {
 	int scaling_mode;
 
 	struct nouveau_encoder *detected_encoder;
-	struct edid *edid;
+	/* Borrowed decoded view of ->drm_edid for the raw-EDID consumers
+	 * (SADs, deep-colour flags, dual-link byte); do not free.
+	 */
+	const struct edid *edid;
+	/* Owner of the sink's EDID, HF-EEODB-complete. */
+	const struct drm_edid *drm_edid;
 	struct drm_display_mode *native_mode;
 #ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT
 	struct nouveau_backlight *backlight;
-- 
2.55.0