Add handling of EDID extension blocks.

5 files changed, 31 insertions, 7 deletions

diff --git a/NEWS b/NEWS
index af96b80..193e5ab 100644
--- a/NEWS
+++ b/NEWS
@@ -5,8 +5,11 @@
     interface on non-x86 hosts as well (fixes Mandriva bug #53866, which
     was caused by a bug in the removed code)
   o fix the retrieval of VBE vendor strings when using the LRMI interface
+  o retrieve up to 4 EDID extension blocks
+
 - monitor-parse-edid:
   o print EDID version and the number of EDID extension blocks
+  o accept EDID data with multiple extension blocks
 
 Version 2.5 - 18 October 2009, by Anssi Hannula
 
diff --git a/get-edid.h b/get-edid.h
index 4b82204..b61dc98 100644
--- a/get-edid.h
+++ b/get-edid.h
@@ -1,3 +1,6 @@
+#define EDID_BLOCK_SIZE		128
+#define MAX_EXTENSION_COUNT	4
+
 int verbose;
 
 int get_edid(char *edid, int port);
diff --git a/monitor-get-edid-using-vbe.c b/monitor-get-edid-using-vbe.c
index ba04224..c70e663 100644
--- a/monitor-get-edid-using-vbe.c
+++ b/monitor-get-edid-using-vbe.c
@@ -15,7 +15,7 @@ int verbose = 0;
 
 int main(int argc, char **argv)
 {
-  char edid[256];
+  char edid[(1 + MAX_EXTENSION_COUNT) * EDID_BLOCK_SIZE];
   int try_in_console = 0;
   int port = 0;
   int i;
diff --git a/monitor-parse-edid b/monitor-parse-edid
index a033c35..68fb32b 100755
--- a/monitor-parse-edid
+++ b/monitor-parse-edid
@@ -487,7 +487,7 @@ sub print_edid {
 sub edid_from_lines {
     my (@l) = @_;
     my $edid_str = join('', map { /\s+([0-9a-f]{32})$/ && $1 } @l);
-    length($edid_str) == 256 or return ();
+    length($edid_str) % (2 * 128) == 0 or return ();
     pack("C*", map { hex($_) } $edid_str =~ /(..)/g);
 }
 
@@ -536,7 +536,7 @@ sub error {
 }
 
 my @raw_edids;
-if (length($input) == 128 || length($input) == 256) {
+if (length($input) % 128 == 0 && length($input) <= 128 * 254) {
     @raw_edids = $input;
 } else {
     @raw_edids = find_edid_in_string($input) or error("bad edid");
diff --git a/vbe.c b/vbe.c
index 8eb74fc..56882d3 100644
--- a/vbe.c
+++ b/vbe.c
@@ -209,11 +209,10 @@ static int vbe_check_ddc_capabilities(int port)
   return 1;
 }
 
-static int vbe_get_edid_info(char *edid, int port)
+static int vbe_get_edid_info(char *edid, int port, int block)
 {
   int i;
   unsigned char *mem;
-  const int EDID_BLOCK_SIZE = 128;
   struct LRMI_regs regs;
 
   /* initialize LRMI */
@@ -235,6 +234,7 @@ static int vbe_get_edid_info(char *edid, int port)
   regs.eax = 0x4f15;
   regs.ebx = 0x0001;
   regs.ecx = port;
+  regs.edx = block;
   regs.es = (uintptr_t)(mem - LRMI_base_addr()) >> 4;
   regs.edi = (uintptr_t)(mem - LRMI_base_addr()) & 0x0f;
 
@@ -262,6 +262,7 @@ static int vbe_get_edid_info(char *edid, int port)
 
 int get_edid(char *edid, int port)
 {
+  int i, extensions;
   int ok = 0;
 
   if (getuid() != 0) {
@@ -272,9 +273,26 @@ int get_edid(char *edid, int port)
   ok =
     (box_is_xbox() || (vbe_check_vbe_info() &&
      vbe_check_ddc_capabilities(port))) &&
-    vbe_get_edid_info(edid, port);
+    vbe_get_edid_info(edid, port, 0);
 
-  return ok ? 128 : 0;
+  if (!ok)
+    return 0;
+
+  extensions = ((unsigned char*)edid)[126];
+  if (extensions > MAX_EXTENSION_COUNT) {
+    log_err("EDID: Reported %d extensions, only reading %d\n",
+            extensions, MAX_EXTENSION_COUNT);
+    extensions = MAX_EXTENSION_COUNT;
+  }
+
+  for (i = 1; i <= extensions; i++) {
+    if (!vbe_get_edid_info(edid + i * EDID_BLOCK_SIZE, port, i)) {
+      log_err("EDID: Failure reading extension block %d\n", i);
+      break;
+    }
+  }
+
+  return i * EDID_BLOCK_SIZE;
 }
 
 int box_is_xbox() {