crtc: match full preferred modes if possible when choosing an initial config

It's fairly common to have multiple, identical monitors plugged in.  In
that case, it's preferable to run the monitor's preferred mode on each
output, rather than just matching the width & height and end up with
different timings or refresh rates.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 20 insertions, 5 deletions

diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index cbe0b5cf6..384d8b472 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -2060,13 +2060,28 @@ xf86TargetPreferred(ScrnInfoPtr scrn, xf86CrtcConfigPtr config,
 		if (o == p)
 		    continue;
 
-		for (mode = output->probed_modes; mode; mode = mode->next) {
-		    Rotation r = output->initial_rotation;
-		    if (xf86ModeWidth(mode, r) == pref_width &&
-			    xf86ModeHeight(mode, r) == pref_height) {
+		/*
+		 * First see if the preferred mode matches on the next
+		 * output as well.  This catches the common case of identical
+		 * monitors and makes sure they all have the same timings
+		 * and refresh.  If that fails, we fall back to trying to
+		 * match just width & height.
+		 */
+		mode = xf86OutputHasPreferredMode(output, pref_width,
+						  pref_height);
+		if (mode && xf86ModesEqual(mode, preferred[p])) {
 			preferred[o] = mode;
 			match = TRUE;
-		    }
+		} else {
+			for (mode = output->probed_modes; mode;
+			     mode = mode->next) {
+				Rotation r = output->initial_rotation;
+				if (xf86ModeWidth(mode, r) == pref_width &&
+				    xf86ModeHeight(mode, r) == pref_height) {
+					preferred[o] = mode;
+					match = TRUE;
+				}
+			}
 		}
 
 		all_match &= match;