modes: Fix duplicate detection, and do it more consistently

Signed-off-by: Adam Jackson <ajax@redhat.com>
(cherry picked from commit 7c0803f555782dbf451b7c79112d7deae02e5c9f)

4 files changed, 39 insertions, 31 deletions

diff --git a/hw/xfree86/modes/xf86Crtc.c b/hw/xfree86/modes/xf86Crtc.c
index 506fbb9cb..937064003 100644
--- a/hw/xfree86/modes/xf86Crtc.c
+++ b/hw/xfree86/modes/xf86Crtc.c
@@ -1377,34 +1377,6 @@ xf86InitialPanning (ScrnInfoPtr scrn)
     }
 }
 
-/*
- * XXX walk the monitor mode list and prune out duplicates that
- * are inserted by xf86DDCMonitorSet. In an ideal world, that
- * function would do this work by itself.
- */
-
-static void
-xf86PruneDuplicateMonitorModes (MonPtr Monitor)
-{
-    DisplayModePtr  master, clone, next;
-
-    for (master = Monitor->Modes; 
-	 master && master != Monitor->Last; 
-	 master = master->next)
-    {
-	for (clone = master->next; clone && clone != Monitor->Modes; clone = next)
-	{
-	    next = clone->next;
-	    if (xf86ModesEqual (master, clone))
-	    {
-		if (Monitor->Last == clone)
-		    Monitor->Last = clone->prev;
-		xf86DeleteMode (&Monitor->Modes, clone);
-	    }
-	}
-    }
-}
-
 /** Return - 0 + if a should be earlier, same or later than b in list
  */
 static int
@@ -1539,9 +1511,6 @@ xf86ProbeOutputModes (ScrnInfoPtr scrn, int maxX, int maxY)
 	maxY = config->maxHeight;
     }
 
-    /* Elide duplicate modes before defaulting code uses them */
-    xf86PruneDuplicateMonitorModes (scrn->monitor);
-    
     /* Probe the list of modes for each output. */
     for (o = 0; o < config->num_output; o++) 
     {
diff --git a/hw/xfree86/modes/xf86EdidModes.c b/hw/xfree86/modes/xf86EdidModes.c
index 5992d95da..93d9f664a 100644
--- a/hw/xfree86/modes/xf86EdidModes.c
+++ b/hw/xfree86/modes/xf86EdidModes.c
@@ -975,6 +975,8 @@ xf86DDCGetModes(int scrnIndex, xf86MonPtr DDC)
     if (quirks & DDC_QUIRK_PREFER_LARGE_75)
 	xf86DDCSetPreferredRefresh(scrnIndex, Modes, 75);
 
+    Modes = xf86PruneDuplicateModes(Modes);
+
     return Modes;
 }
 
diff --git a/hw/xfree86/modes/xf86Modes.c b/hw/xfree86/modes/xf86Modes.c
index d105b48ab..862a4734b 100644
--- a/hw/xfree86/modes/xf86Modes.c
+++ b/hw/xfree86/modes/xf86Modes.c
@@ -689,3 +689,37 @@ xf86GetDefaultModes (void)
     }
     return head;
 }
+
+/*
+ * Walk a mode list and prune out duplicates.  Will preserve the preferred
+ * mode of an otherwise-duplicate pair.
+ *
+ * Probably best to call this on lists that are all of a single class
+ * (driver, default, user, etc.), otherwise, which mode gets deleted is
+ * not especially well defined.
+ *
+ * Returns the new list.
+ */
+
+DisplayModePtr
+xf86PruneDuplicateModes(DisplayModePtr modes)
+{
+    DisplayModePtr m, n, o;
+
+top:
+    for (m = modes; m; m = m->next) {
+	for (n = m->next; n; n = o) {
+	    o = n->next;
+	    if (xf86ModesEqual(m, n)) {
+		if (n->type & M_T_PREFERRED) {
+		    xf86DeleteMode(&modes, m);
+		    goto top;
+		}
+		else
+		    xf86DeleteMode(&modes, n);
+	    }
+	}
+    }
+
+    return modes;
+}
diff --git a/hw/xfree86/modes/xf86Modes.h b/hw/xfree86/modes/xf86Modes.h
index 908f59b48..38927b128 100644
--- a/hw/xfree86/modes/xf86Modes.h
+++ b/hw/xfree86/modes/xf86Modes.h
@@ -95,6 +95,9 @@ extern _X_EXPORT void
 xf86PruneInvalidModes(ScrnInfoPtr pScrn, DisplayModePtr *modeList,
 		      Bool verbose);
 
+extern _X_EXPORT DisplayModePtr
+xf86PruneDuplicateModes(DisplayModePtr modes);
+
 extern _X_EXPORT void
 xf86ValidateModesFlags(ScrnInfoPtr pScrn, DisplayModePtr modeList,
 		       int flags);