drm/displayid: Iterate over all DisplayID blocks

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: Tomas Bzatek <tomas@bzatek.net>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 4724596ebf53b9c82262ea8faa375c962aa05de8..0b95a7f2db031bdc64b61883497ed003922238d5 100644 (file)
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4237,19 +4237,25 @@ static int drm_parse_display_id(struct drm_connector *connector,
                return -EINVAL;
        }
 
-       block = (struct displayid_block *)&displayid[idx + 4];
-       DRM_DEBUG_KMS("block id %d, rev %d, len %d\n",
-                     block->tag, block->rev, block->num_bytes);
-
-       switch (block->tag) {
-       case DATA_BLOCK_TILED_DISPLAY:
-               ret = drm_parse_tiled_block(connector, block);
-               if (ret)
-                       return ret;
-               break;
-       default:
-               printk("unknown displayid tag %d\n", block->tag);
-               break;
+       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:
+                       ret = drm_parse_tiled_block(connector, block);
+                       if (ret)
+                               return ret;
+                       break;
+               default:
+                       DRM_DEBUG_KMS("found DisplayID tag 0x%x, unhandled\n", block->tag);
+                       break;
+               }
        }
        return 0;
 }