New patch to review for coreboot: 095c784 edid: Fix extension parsing when EDID blob does not have any extensions.

[Isaac Christensen]

Isaac Christensen ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/6995

-gerrit

commit 095c784f66bb12647ea0eefe96782a3777d62088
Author: Hung-Te Lin 
Date:   Thu Apr 3 18:35:58 2014 +0800

edid: Fix extension parsing when EDID blob does not have any extensions.

When parsing "extensions", we should skip the first EDID (main) block and start
    from offset 128 (EDID may have only main block, so an EDID without any
    extension is fine) because the header format for main block and extensions are
    different.

Without this we will see "Unknown extension block" on all EDIDs, and seeing a
    error (1) return value for EDIDs without extension.

Also, after the first "unknown" error is fixed, we can now collect all return
    values from parse_extension, and give error when any of the extensions are wrong
    (not just last one).

Change-Id: I0ee029ac8ec6800687cd7749e23989399e721109
    Signed-off-by: Hung-Te Lin 
    Reviewed-on: https://chromium-review.googlesource.com/193011
    (cherry picked from commit fdf0cc2e9573c19b550fa2b5e4e06337b114f864)
    Signed-off-by: Isaac Christensen 
---
 src/lib/edid.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/lib/edid.c b/src/lib/edid.c
index 0dc86d5..6bd471a 100644
--- a/src/lib/edid.c
+++ b/src/lib/edid.c
@@ -1261,8 +1261,14 @@ int decode_edid(unsigned char *edid, int size, struct edid *out)

printk(BIOS_SPEW, "Checksum\n");
    do_checksum(edid);
-	for(i = 0; i < size; i += 128)
-		nonconformant_extension = parse_extension(out, &edid[i]);
+
+	/* EDID v2.0 has a larger blob (256 bytes) and may have some problem in
+	 * the extension parsing loop below.  Since v2.0 was quickly deprecated
+	 * by v1.3 and we are unlikely to use any EDID 2.0 panels, we ignore
+	 * that case now and can fix it when we need to use a real 2.0 panel.
+	 */
+	for(i = 128; i < size; i += 128)
+		nonconformant_extension += parse_extension(out, &edid[i]);
    /*
     * x = edid;
     * for (edid_lines /= 8; edid_lines > 1; edid_lines--) {