From d1c48955f80692a32ab6adcee1384e3d298f471a Mon Sep 17 00:00:00 2001
From: Adam Jackson <ajax@redhat.com>
Date: Sat, 12 Jan 2008 00:30:58 -0500
Subject: [PATCH] Fix CVT abuse in DDCModesFromStandardTiming.

CVT is enough different from GTF that it should not be used on monitors
that aren't expecting it.  This brings us closer to what the spec says
the correct behaviour is.
---
 hw/xfree86/ddc/edid.h            |  2 ++
 hw/xfree86/modes/xf86EdidModes.c | 40 +++++++++++++++++++++++++-------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/hw/xfree86/ddc/edid.h b/hw/xfree86/ddc/edid.h
index 2496e19e6..c03427683 100644
--- a/hw/xfree86/ddc/edid.h
+++ b/hw/xfree86/ddc/edid.h
@@ -339,6 +339,8 @@
 #define STD_COLOR_SPACE(x) (x & 0x4)
 #define PREFERRED_TIMING_MODE(x) (x & 0x2)
 #define GFT_SUPPORTED(x) (x & 0x1)
+#define GTF_SUPPORTED(x) (x & 0x1)
+#define CVT_SUPPORTED(x) (x & 0x1)
 
 /* detailed timing misc */
 #define IS_INTERLACED(x)  (x) 
diff --git a/hw/xfree86/modes/xf86EdidModes.c b/hw/xfree86/modes/xf86EdidModes.c
index 467f03251..a9d672265 100644
--- a/hw/xfree86/modes/xf86EdidModes.c
+++ b/hw/xfree86/modes/xf86EdidModes.c
@@ -263,6 +263,22 @@ DDCModesFromEstablished(int scrnIndex, struct established_timings *timing,
     return Modes;
 }
 
+#define LEVEL_DMT 0
+#define LEVEL_GTF 1
+#define LEVEL_CVT 2
+
+static int
+MonitorStandardTimingLevel(xf86MonPtr DDC)
+{
+    if (DDC->ver.revision >= 2) {
+	if (DDC->ver.revision >= 4 && CVT_SUPPORTED(DDC->features.msc)) {
+	    return LEVEL_CVT;
+	}
+	return LEVEL_GTF;
+    }
+    return LEVEL_DMT;
+}
+
 /*
  * This is not really correct.  Appendix B of the EDID 1.4 spec defines
  * the right thing to do here.  If the timing given here matches a mode
@@ -282,16 +298,22 @@ DDCModesFromEstablished(int scrnIndex, struct established_timings *timing,
  * for modes in this section, but does say that CVT is preferred.
  */
 static DisplayModePtr
-DDCModesFromStandardTiming(int scrnIndex, struct std_timings *timing,
-			   ddc_quirk_t quirks)
+DDCModesFromStandardTiming(struct std_timings *timing, ddc_quirk_t quirks,
+			   int timing_level)
 {
     DisplayModePtr Modes = NULL, Mode = NULL;
     int i;
 
     for (i = 0; i < STD_TIMINGS; i++) {
         if (timing[i].hsize && timing[i].vsize && timing[i].refresh) {
-            Mode =  xf86CVTMode(timing[i].hsize, timing[i].vsize,
-                                timing[i].refresh, FALSE, FALSE);
+	    /* XXX check for DMT first, else... */
+	    if (timing_level == LEVEL_CVT)
+		Mode = xf86CVTMode(timing[i].hsize, timing[i].vsize,
+				   timing[i].refresh, FALSE, FALSE);
+	    else
+		Mode = xf86GTFMode(timing[i].hsize, timing[i].vsize,
+				   timing[i].refresh, FALSE, FALSE);
+
 	    Mode->type = M_T_DRIVER;
             Modes = xf86ModesAdd(Modes, Mode);
         }
@@ -565,6 +587,7 @@ xf86DDCGetModes(int scrnIndex, xf86MonPtr DDC)
     DisplayModePtr  Modes = NULL, Mode;
     ddc_quirk_t	    quirks;
     Bool	    preferred;
+    int		    timing_level;
 
     xf86DrvMsg (scrnIndex, X_INFO, "EDID vendor \"%s\", prod id %d\n",
 		DDC->vendor.name, DDC->vendor.prod_id);
@@ -579,6 +602,8 @@ xf86DDCGetModes(int scrnIndex, xf86MonPtr DDC)
     if (quirks & (DDC_QUIRK_PREFER_LARGE_60 | DDC_QUIRK_PREFER_LARGE_75))
 	preferred = FALSE;
 
+    timing_level = MonitorStandardTimingLevel(DDC);
+
     for (i = 0; i < DET_TIMINGS; i++) {
 	struct detailed_monitor_section *det_mon = &DDC->det_mon[i];
 
@@ -592,9 +617,8 @@ xf86DDCGetModes(int scrnIndex, xf86MonPtr DDC)
             Modes = xf86ModesAdd(Modes, Mode);
             break;
         case DS_STD_TIMINGS:
-            Mode = DDCModesFromStandardTiming(scrnIndex,
-					      det_mon->section.std_t,
-					      quirks);
+            Mode = DDCModesFromStandardTiming(det_mon->section.std_t,
+					      quirks, timing_level);
             Modes = xf86ModesAdd(Modes, Mode);
             break;
 	case DS_CVT:
@@ -611,7 +635,7 @@ xf86DDCGetModes(int scrnIndex, xf86MonPtr DDC)
     Modes = xf86ModesAdd(Modes, Mode);
 
     /* Add standard timings */
-    Mode = DDCModesFromStandardTiming(scrnIndex, DDC->timings2, quirks);
+    Mode = DDCModesFromStandardTiming(DDC->timings2, quirks, timing_level);
     Modes = xf86ModesAdd(Modes, Mode);
 
     if (quirks & DDC_QUIRK_PREFER_LARGE_60)