From 96111c154713600dd534dd82104ac18b91466202 Mon Sep 17 00:00:00 2001
From: Adam Jackson <ajax@redhat.com>
Date: Fri, 16 May 2008 10:31:58 -0400
Subject: [PATCH] Redo RANDR compatibility output selection.

Old logic was just the first one that happened to have an associated
CRTC.  The new logic tries to find one that's definitely connected, has
probed modes, and has the largest candidate mode.
---
 hw/xfree86/modes/xf86Crtc.c | 132 ++++++++++++++++++++++++++----------
 1 file changed, 96 insertions(+), 36 deletions(-)

diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index 402336fe9..1b6bb9fea 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -1593,7 +1593,98 @@ xf86ProbeOutputModes (ScrnInfoPtr scrn, int maxX, int maxY)
 _X_EXPORT void
 xf86RandR12GetOriginalVirtualSize(ScrnInfoPtr scrn, int *x, int *y);
 
-_X_EXPORT void
+static DisplayModePtr
+biggestMode(DisplayModePtr a, DisplayModePtr b)
+{
+    int A, B;
+
+    if (!a)
+	return b;
+    if (!b)
+	return a;
+
+    A = a->HDisplay * a->VDisplay;
+    B = b->HDisplay * b->VDisplay;
+
+    if (A > B)
+	return a;
+
+    return b;
+}
+
+static xf86OutputPtr
+SetCompatOutput(xf86CrtcConfigPtr config)
+{
+    xf86OutputPtr output = NULL, test = NULL;
+    DisplayModePtr maxmode = NULL, testmode, mode;
+    int o, compat = -1, count, mincount = 0;
+
+    /* Look for one that's definitely connected */
+    for (o = 0; o < config->num_output; o++)
+    {
+	test = config->output[o];
+	if (!test->crtc)
+	    continue;
+	if (test->status != XF86OutputStatusConnected)
+	    continue;
+	if (!test->probed_modes)
+	    continue;
+
+	testmode = mode = test->probed_modes;
+	for (count = 0; mode; mode = mode->next, count++)
+	    testmode = biggestMode(testmode, mode);
+
+	if (!output) {
+	    output = test;
+	    compat = o;
+	    maxmode = testmode;
+	    mincount = count;
+	} else if (maxmode == biggestMode(maxmode, testmode)) {
+	    output = test;
+	    compat = o;
+	    maxmode = testmode;
+	    mincount = count;
+	} else if ((maxmode->HDisplay == testmode->HDisplay) && 
+		(maxmode->VDisplay == testmode->VDisplay) &&
+		count <= mincount) {
+	    output = test;
+	    compat = o;
+	    maxmode = testmode;
+	    mincount = count;
+	}
+    }
+
+    /* If we didn't find one, take anything we can get */
+    if (!output)
+    {
+	for (o = 0; o < config->num_output; o++)
+	{
+	    test = config->output[o];
+	    if (!test->crtc)
+		continue;
+	    if (!test->probed_modes)
+		continue;
+
+	    if (!output) {
+		output = test;
+		compat = o;
+	    } else if (test->probed_modes->HDisplay < output->probed_modes->HDisplay) {
+		output = test;
+		compat = o;
+	    }
+	}
+    }
+
+    if (compat >= 0) {
+	config->compat_output = compat;
+    } else {
+	/* Don't change the compat output when no valid outputs found */
+	output = config->output[config->compat_output];
+    }
+
+    return output;
+}
+
 xf86SetScrnInfoModes (ScrnInfoPtr scrn)
 {
     xf86CrtcConfigPtr	config = XF86_CRTC_CONFIG_PTR(scrn);
@@ -1601,23 +1692,11 @@ xf86SetScrnInfoModes (ScrnInfoPtr scrn)
     xf86CrtcPtr		crtc;
     DisplayModePtr	last, mode;
 
-    output = config->output[config->compat_output];
-    if (!output->crtc)
-    {
-	int o;
+    output = SetCompatOutput(config);
+
+    if (!output)
+	return; /* punt */
 
-	output = NULL;
-	for (o = 0; o < config->num_output; o++)
-	    if (config->output[o]->crtc)
-	    {
-		config->compat_output = o;
-		output = config->output[o];
-		break;
-	    }
-	/* no outputs are active, punt and leave things as they are */
-	if (!output)
-	    return;
-    }
     crtc = output->crtc;
 
     /* Clear any existing modes from scrn->modes */
@@ -1782,25 +1861,6 @@ bestModeForAspect(xf86CrtcConfigPtr config, Bool *enabled, float aspect)
     return match;
 }
 
-static DisplayModePtr
-biggestMode(DisplayModePtr a, DisplayModePtr b)
-{
-    int A, B;
-
-    if (!a)
-	return b;
-    if (!b)
-	return a;
-
-    A = a->HDisplay * a->VDisplay;
-    B = b->HDisplay * b->VDisplay;
-
-    if (A > B)
-	return a;
-
-    return b;
-}
-
 static Bool
 xf86TargetAspect(ScrnInfoPtr scrn, xf86CrtcConfigPtr config,
 		 DisplayModePtr *modes, Bool *enabled,