monitor-parse-edid:

 ignore the Manufacturer Specified Range Timing descriptor if the
 first detailed timing descriptor appears to violate it (this probably
 means that the descriptor is actually something else or in a
 different format; this fixes Lenovo W500 detection, reported by Udo
 Rader)

2 files changed, 17 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index 94a99df..f5259d8 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+- monitor-parse-edid:
+  o ignore the Manufacturer Specified Range Timing descriptor if the
+    first detailed timing descriptor appears to violate it (this probably
+    means that the descriptor is actually something else or in a
+    different format; this fixes Lenovo W500 detection, reported by Udo
+    Rader)
+
 Version 2.3 - 6 September 2009
 
 - monitor-get-edid-using-vbe:
diff --git a/monitor-parse-edid b/monitor-parse-edid
index c6e158c..f559136 100755
--- a/monitor-parse-edid
+++ b/monitor-parse-edid
@@ -140,6 +140,11 @@ my %subfields = (
     ) ],
 );
 
+sub within_limit {
+    my ($value, $type, $limit) = @_;
+    $type eq 'min' ? $value >= $limit : $value <= $limit;
+}
+
 sub get_many_bits {
     my ($s, $field_name) = @_;
     my @bits = split('', unpack('B*', $s));
@@ -250,7 +255,11 @@ sub parse_edid {
 				$range->{$dir . '_sync_pulse_width_' . $m} *= 2;
 				$range->{$dir . '_back_porch_' . $m} *= 2;
 				$range->{$dir . '_blanking_' . $m} *= 2;
-				if ($e && $e->{$dir . '_active'}) {
+				if ($e && $e->{$dir . '_active'}
+				    && within_limit($e->{$dir . '_blanking'}, $m, $range->{$dir . '_blanking_' . $m})
+				    && within_limit($e->{$dir . '_sync_pulse_width'}, $m, $range->{$dir . '_sync_pulse_width_' . $m})
+				    && within_limit($e->{$dir . '_blanking'} - $e->{$dir . '_sync_offset'} - $e->{$dir . '_sync_pulse_width'},
+					    $m, $range->{$dir . '_back_porch_' . $m})) {
 				    $total{$dir} = $e->{$dir . '_active'} + $range->{$dir . '_blanking_' . $m};
 				}
 			    }