[PATCH 2/5] drm/displayid: Iterate over all DisplayID blocks

[Dave Airlie]

From: Tomas Bzatek <tomas at bzatek.net>

This will iterate over all DisplayID blocks found in the buffer.
Previously only the first block was parsed.

https://bugs.freedesktop.org/show_bug.cgi?id=95207

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/drm_edid.c | 124 ++++++++++++++++++++++++---------------------
 1 file changed, 65 insertions(+), 59 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index c8a3a55..1a364b3 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4182,66 +4182,72 @@ static int drm_parse_display_id(struct drm_connector *connector,
 		return -EINVAL;
 	}
 
-	block = (struct displayid_block *)&displayid[idx + 4];
-	DRM_DEBUG_KMS("block id 0x%x, rev %d, len %d\n",
-		      block->tag, block->rev, block->num_bytes);
-
-	switch (block->tag) {
-	case DATA_BLOCK_TILED_DISPLAY: {
-		struct displayid_tiled_block *tile = (struct displayid_tiled_block *)block;
-
-		u16 w, h;
-		u8 tile_v_loc, tile_h_loc;
-		u8 num_v_tile, num_h_tile;
-		struct drm_tile_group *tg;
-
-		w = tile->tile_size[0] | tile->tile_size[1] << 8;
-		h = tile->tile_size[2] | tile->tile_size[3] << 8;
-
-		num_v_tile = (tile->topo[0] & 0xf) | (tile->topo[2] & 0x30);
-		num_h_tile = (tile->topo[0] >> 4) | ((tile->topo[2] >> 2) & 0x30);
-		tile_v_loc = (tile->topo[1] & 0xf) | ((tile->topo[2] & 0x3) << 4);
-		tile_h_loc = (tile->topo[1] >> 4) | (((tile->topo[2] >> 2) & 0x3) << 4);
-
-		connector->has_tile = true;
-		if (tile->tile_cap & 0x80)
-			connector->tile_is_single_monitor = true;
-
-		connector->num_h_tile = num_h_tile + 1;
-		connector->num_v_tile = num_v_tile + 1;
-		connector->tile_h_loc = tile_h_loc;
-		connector->tile_v_loc = tile_v_loc;
-		connector->tile_h_size = w + 1;
-		connector->tile_v_size = h + 1;
-
-		DRM_DEBUG_KMS("tile cap 0x%x\n", tile->tile_cap);
-		DRM_DEBUG_KMS("tile_size %d x %d\n", w + 1, h + 1);
-		DRM_DEBUG_KMS("topo num tiles %dx%d, location %dx%d\n",
-		       num_h_tile + 1, num_v_tile + 1, tile_h_loc, tile_v_loc);
-		DRM_DEBUG_KMS("vend %c%c%c\n", tile->topology_id[0], tile->topology_id[1], tile->topology_id[2]);
-
-		tg = drm_mode_get_tile_group(connector->dev, tile->topology_id);
-		if (!tg) {
-			tg = drm_mode_create_tile_group(connector->dev, tile->topology_id);
-		}
-		if (!tg)
-			return -ENOMEM;
-
-		if (connector->tile_group != tg) {
-			/* if we haven't got a pointer,
-			   take the reference, drop ref to old tile group */
-			if (connector->tile_group) {
-				drm_mode_put_tile_group(connector->dev, connector->tile_group);
+	idx += sizeof(struct displayid_hdr);
+	while (block = (struct displayid_block *)&displayid[idx],
+	       idx + sizeof(struct displayid_block) <= length &&
+	       idx + sizeof(struct displayid_block) + block->num_bytes <= length &&
+	       block->num_bytes > 0) {
+		idx += block->num_bytes + sizeof(struct displayid_block);
+		DRM_DEBUG_KMS("block id 0x%x, rev %d, len %d\n",
+			      block->tag, block->rev, block->num_bytes);
+
+		switch (block->tag) {
+		case DATA_BLOCK_TILED_DISPLAY: {
+			struct displayid_tiled_block *tile = (struct displayid_tiled_block *)block;
+
+			u16 w, h;
+			u8 tile_v_loc, tile_h_loc;
+			u8 num_v_tile, num_h_tile;
+			struct drm_tile_group *tg;
+
+			w = tile->tile_size[0] | tile->tile_size[1] << 8;
+			h = tile->tile_size[2] | tile->tile_size[3] << 8;
+
+			num_v_tile = (tile->topo[0] & 0xf) | (tile->topo[2] & 0x30);
+			num_h_tile = (tile->topo[0] >> 4) | ((tile->topo[2] >> 2) & 0x30);
+			tile_v_loc = (tile->topo[1] & 0xf) | ((tile->topo[2] & 0x3) << 4);
+			tile_h_loc = (tile->topo[1] >> 4) | (((tile->topo[2] >> 2) & 0x3) << 4);
+
+			connector->has_tile = true;
+			if (tile->tile_cap & 0x80)
+				connector->tile_is_single_monitor = true;
+
+			connector->num_h_tile = num_h_tile + 1;
+			connector->num_v_tile = num_v_tile + 1;
+			connector->tile_h_loc = tile_h_loc;
+			connector->tile_v_loc = tile_v_loc;
+			connector->tile_h_size = w + 1;
+			connector->tile_v_size = h + 1;
+
+			DRM_DEBUG_KMS("tile cap 0x%x\n", tile->tile_cap);
+			DRM_DEBUG_KMS("tile_size %d x %d\n", w + 1, h + 1);
+			DRM_DEBUG_KMS("topo num tiles %dx%d, location %dx%d\n",
+			       num_h_tile + 1, num_v_tile + 1, tile_h_loc, tile_v_loc);
+			DRM_DEBUG_KMS("vend %c%c%c\n", tile->topology_id[0], tile->topology_id[1], tile->topology_id[2]);
+
+			tg = drm_mode_get_tile_group(connector->dev, tile->topology_id);
+			if (!tg) {
+				tg = drm_mode_create_tile_group(connector->dev, tile->topology_id);
 			}
-			connector->tile_group = tg;
-		} else
-			/* if same tile group, then release the ref we just took. */
-			drm_mode_put_tile_group(connector->dev, tg);
-	}
-		break;
-	default:
-		printk("unknown displayid tag %d\n", block->tag);
-		break;
+			if (!tg)
+				return -ENOMEM;
+
+			if (connector->tile_group != tg) {
+				/* if we haven't got a pointer,
+				   take the reference, drop ref to old tile group */
+				if (connector->tile_group) {
+					drm_mode_put_tile_group(connector->dev, connector->tile_group);
+				}
+				connector->tile_group = tg;
+			} else
+				/* if same tile group, then release the ref we just took. */
+				drm_mode_put_tile_group(connector->dev, tg);
+		}
+			break;
+		default:
+			DRM_DEBUG_KMS("found DisplayID tag 0x%x, unhandled\n", block->tag);
+			break;
+		}
 	}
 	return 0;
 }
-- 
2.5.5