Bug #5386: Synthesize modelines from EDID data.

2 files changed, 378 insertions, 127 deletions

diff --git a/hw/xfree86/ddc/ddcProperty.c b/hw/xfree86/ddc/ddcProperty.c
index 22deca687..ed7fb167a 100644
--- a/hw/xfree86/ddc/ddcProperty.c
+++ b/hw/xfree86/ddc/ddcProperty.c
@@ -1,159 +1,407 @@
-/* ddcProperty.c: Make the DDC monitor information available to clients
- * as properties on the root window
- * 
- * Copyright 1999 by Andrew C Aitchison <A.C.Aitchison@dpmms.cam.ac.uk>
+/*
+ * Copyright 2006 Luc Verhaegen.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sub license,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
  */
 
 #ifdef HAVE_XORG_CONFIG_H
 #include <xorg-config.h>
 #endif
 
-#include <string.h>
-#include "misc.h"
 #include "xf86.h"
-/* #include "xf86_OSproc.h" */
-#include <X11/Xatom.h>
-#include "property.h"
-#include "propertyst.h"
 #include "xf86DDC.h"
 
-#define EDID1_ATOM_NAME         "XFree86_DDC_EDID1_RAWDATA"
-#define EDID2_ATOM_NAME         "XFree86_DDC_EDID2_RAWDATA"
-#define VDIF_ATOM_NAME          "XFree86_DDC_VDIF_RAWDATA"
-
-Bool
-xf86SetDDCproperties(ScrnInfoPtr pScrnInfo, xf86MonPtr DDC)
+/*
+ * xf86Mode.c should have a some more DisplayModePtr list handling.
+ */
+static DisplayModePtr
+xf86ModesAdd(DisplayModePtr Modes, DisplayModePtr Additions)
 {
-    Atom EDID1Atom=-1, EDID2Atom=-1, VDIFAtom=-1;
-    CARD8 *EDID1rawdata = NULL;
-    CARD8 *EDID2rawdata = NULL;
-    int  i, ret;
-    Bool  makeEDID1prop = FALSE;
-    Bool  makeEDID2prop = FALSE;
-
-#ifdef DEBUG
-    ErrorF("xf86SetDDCproperties(%p, %p)\n", pScrnInfo, DDC);
-#endif
+    if (!Modes) {
+        if (Additions)
+            return Additions;
+        else
+            return NULL;
+    }
 
-    if (pScrnInfo==NULL || pScrnInfo->monitor==NULL || DDC==NULL) {
-      return FALSE;
+    if (Additions) {
+        DisplayModePtr Mode = Modes;
+
+        while (Mode->next)
+            Mode = Mode->next;
+        
+        Mode->next = Additions;
+        Additions->prev = Mode;
     }
 
-#ifdef DEBUG
-    ErrorF("pScrnInfo->scrnIndex %d\n", pScrnInfo->scrnIndex);
+    return Modes;
+}
+
+static DisplayModePtr
+xf86ModeCopy(DisplayModePtr Mode)
+{
+    DisplayModePtr New;
+
+    if (!Mode)
+        return NULL;
+
+    New = xnfalloc(sizeof(DisplayModeRec));
+
+    memcpy(New, Mode, sizeof(DisplayModeRec));
+    
+    New->name = xnfalloc(strlen(Mode->name) + 1);
+    memcpy(New->name, Mode->name, strlen(Mode->name) + 1);
+
+    /* We ignore privates as DDC code doesn't use it currently */
+    return New;
+}
+
+/*
+ * Temporary.
+ */
+static void
+add(char **p, char *new)
+{
+    *p = xnfrealloc(*p, strlen(*p) + strlen(new) + 2);
+    strcat(*p, " ");
+    strcat(*p, new);
+}
 
-    ErrorF("pScrnInfo->monitor was %p\n", pScrnInfo->monitor);
+static void
+PrintModeline(int scrnIndex,DisplayModePtr mode)
+{
+    char tmp[256];
+    char *flags = xnfcalloc(1, 1);
+
+    if (mode->HSkew) { 
+	snprintf(tmp, 256, "hskew %i", mode->HSkew); 
+	add(&flags, tmp);
+    }
+    if (mode->VScan) { 
+	snprintf(tmp, 256, "vscan %i", mode->VScan); 
+	add(&flags, tmp);
+    }
+    if (mode->Flags & V_INTERLACE) add(&flags, "interlace");
+    if (mode->Flags & V_CSYNC) add(&flags, "composite");
+    if (mode->Flags & V_DBLSCAN) add(&flags, "doublescan");
+    if (mode->Flags & V_BCAST) add(&flags, "bcast");
+    if (mode->Flags & V_PHSYNC) add(&flags, "+hsync");
+    if (mode->Flags & V_NHSYNC) add(&flags, "-hsync");
+    if (mode->Flags & V_PVSYNC) add(&flags, "+vsync");
+    if (mode->Flags & V_NVSYNC) add(&flags, "-vsync");
+    if (mode->Flags & V_PCSYNC) add(&flags, "+csync");
+    if (mode->Flags & V_NCSYNC) add(&flags, "-csync");
+#if 0
+    if (mode->Flags & V_CLKDIV2) add(&flags, "vclk/2");
 #endif
+    xf86DrvMsgVerb(scrnIndex, X_INFO, 3,
+		   "Modeline \"%s\"  %6.2f  %i %i %i %i  %i %i %i %i%s\n",
+		   mode->name, mode->Clock/1000., mode->HDisplay,
+		   mode->HSyncStart, mode->HSyncEnd, mode->HTotal,
+		   mode->VDisplay, mode->VSyncStart, mode->VSyncEnd,
+		   mode->VTotal, flags);
+    xfree(flags);
+}
+
+/*
+ * TODO:
+ *  - for those with access to the VESA DMT standard; review please.
+ *  - swap M_T_DEFAULT for M_T_EDID_...
+ */
+#define MODEPREFIX(name) NULL, NULL, name, 0,M_T_DEFAULT
+#define MODESUFFIX   0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,FALSE,FALSE,0,NULL,0,0.0,0.0
+
+DisplayModeRec DDCEstablishedModes[17] = {
+    { MODEPREFIX("800x600"),    40000,  800,  840,  968, 1056, 0,  600,  601,  605,  628, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 800x600@60Hz */
+    { MODEPREFIX("800x600"),    36000,  800,  824,  896, 1024, 0,  600,  601,  603,  625, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 800x600@56Hz */
+    { MODEPREFIX("640x480"),    31500,  640,  656,  720,  840, 0,  480,  481,  484,  500, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 640x480@75Hz */
+    { MODEPREFIX("640x480"),    31500,  640,  664,  704,  832, 0,  480,  489,  491,  520, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 640x480@72Hz */
+    { MODEPREFIX("640x480"),    30240,  640,  704,  768,  864, 0,  480,  483,  486,  525, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 640x480@67Hz */
+    { MODEPREFIX("640x480"),    25200,  640,  656,  752,  800, 0,  480,  490,  492,  525, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 640x480@60Hz */
+    { MODEPREFIX("720x400"),    35500,  720,  738,  846,  900, 0,  400,  421,  423,  449, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 720x400@88Hz */
+    { MODEPREFIX("720x400"),    28320,  720,  738,  846,  900, 0,  400,  412,  414,  449, 0, V_NHSYNC | V_PVSYNC, MODESUFFIX }, /* 720x400@70Hz */
+    { MODEPREFIX("1280x1024"), 135000, 1280, 1296, 1440, 1688, 0, 1024, 1025, 1028, 1066, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 1280x1024@75Hz */
+    { MODEPREFIX("1024x768"),   78800, 1024, 1040, 1136, 1312, 0,  768,  769,  772,  800, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 1024x768@75Hz */
+    { MODEPREFIX("1024x768"),   75000, 1024, 1048, 1184, 1328, 0,  768,  771,  777,  806, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 1024x768@70Hz */
+    { MODEPREFIX("1024x768"),   65000, 1024, 1048, 1184, 1344, 0,  768,  771,  777,  806, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 1024x768@60Hz */
+    { MODEPREFIX("1024x768"),   44900, 1024, 1032, 1208, 1264, 0,  768,  768,  776,  817, 0, V_PHSYNC | V_PVSYNC | V_INTERLACE, MODESUFFIX }, /* 1024x768@43Hz */
+    { MODEPREFIX("832x624"),    57284,  832,  864,  928, 1152, 0,  624,  625,  628,  667, 0, V_NHSYNC | V_NVSYNC, MODESUFFIX }, /* 832x624@75Hz */
+    { MODEPREFIX("800x600"),    49500,  800,  816,  896, 1056, 0,  600,  601,  604,  625, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 800x600@75Hz */
+    { MODEPREFIX("800x600"),    50000,  800,  856,  976, 1040, 0,  600,  637,  643,  666, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 800x600@72Hz */
+    { MODEPREFIX("1152x864"),  108000, 1152, 1216, 1344, 1600, 0,  864,  865,  868,  900, 0, V_PHSYNC | V_PVSYNC, MODESUFFIX }, /* 1152x864@75Hz */
+};
+
+static DisplayModePtr
+DDCModesFromEstablished(int scrnIndex, struct established_timings *timing)
+{
+    DisplayModePtr Modes = NULL, Mode = NULL;
+    CARD32 bits = (timing->t1) | (timing->t2 << 8) |
+        ((timing->t_manu & 0x80) << 9);
+    int i;
+
+    for (i = 0; i < 17; i++)
+        if (bits & (0x01 << i)) {
+            Mode = xf86ModeCopy(&(DDCEstablishedModes[i]));
+            Modes = xf86ModesAdd(Modes, Mode);
+        }
+
+    return Modes;
+}
+
+/*
+ *
+ */
+static DisplayModePtr
+DDCModesFromStandardTiming(int scrnIndex, struct std_timings *timing)
+{
+    DisplayModePtr Modes = NULL, Mode = NULL;
+    int i;
+    
+    for (i = 0; i < 5; i++)
+        if (timing[i].hsize && timing[i].vsize && timing[i].refresh) {
+            Mode =  xf86CVTMode(timing[i].hsize, timing[i].vsize,
+                                timing[i].refresh, FALSE, FALSE);
+            Modes = xf86ModesAdd(Modes, Mode);
+        }
+
+    return Modes;
+}
 
-    pScrnInfo->monitor->DDC = DDC;
-
-    if (DDC->ver.version == 1) {
-      makeEDID1prop = TRUE;
-    } else if (DDC->ver.version == 2) {
-      int checksum1;
-      int checksum2;
-      makeEDID2prop = TRUE;
-
-      /* Some monitors (eg Panasonic PanaSync4)
-       * report version==2 because they used EDID v2 spec document,
-       * although they use EDID v1 data structure :-(
-       *
-       * Try using checksum to determine when we have such a monitor.
-       */
-      checksum2 = 0;
-      for (i=0; i<256; i++) { checksum2 += DDC->rawData[i]; }
-      if ( (checksum2 % 256) != 0 ) {
-	xf86DrvMsg(pScrnInfo->scrnIndex,X_INFO, "Monitor EDID v2 checksum failed\n");
-	xf86DrvMsg(pScrnInfo->scrnIndex,X_INFO, "XFree86_DDC_EDID2_RAWDATA property may be bad\n");
-	checksum1 = 0;
-	for (i=0; i<128; i++) { checksum1 += DDC->rawData[i]; }
-	if ( (checksum1 % 256) == 0 ) {
-	  xf86DrvMsg(pScrnInfo->scrnIndex,X_INFO, "Monitor EDID v1 checksum passed,\n");
-	  xf86DrvMsg(pScrnInfo->scrnIndex,X_INFO, "XFree86_DDC_EDID1_RAWDATA property created\n");
-	  makeEDID1prop = TRUE;
-	}
-      }
-    } else {
-     xf86DrvMsg(pScrnInfo->scrnIndex, X_PROBED,
-		"unexpected EDID version %d revision %d\n",
-		DDC->ver.version, DDC->ver.revision );      
+/*
+ *
+ */
+static DisplayModePtr
+DDCModeFromDetailedTiming(int scrnIndex, struct detailed_timings *timing)
+{
+    DisplayModePtr Mode;
+
+    /* We don't do stereo */
+    if (timing->stereo) {
+        xf86DrvMsg(scrnIndex, X_INFO, "%s: Ignoring: We don't handle stereo.\n",
+                   __func__);
+        return NULL;
+    }
+    
+    /* We only do seperate sync currently */
+    if (timing->sync != 0x03) {
+         xf86DrvMsg(scrnIndex, X_INFO, "%s: Ignoring: We only handle seperate"
+                    " sync.\n", __func__);
+         return NULL;
     }
+    
+    Mode = xnfalloc(sizeof(DisplayModeRec));
+    memset(Mode, 0, sizeof(DisplayModeRec));
+    
+    Mode->name = xnfalloc(10); /* "1234x1234" */
+    xf86snprintf(Mode->name, 20, "%dx%d", timing->h_active,
+                 timing->v_active);
+    
+    Mode->type = M_T_DEFAULT; /* get ourselves a nice type of our own */
+    
+    Mode->Clock = timing->clock / 1000.0;
+    
+    Mode->HDisplay = timing->h_active;
+    Mode->HSyncStart = timing->h_active + timing->h_sync_off;
+    Mode->HSyncEnd = Mode->HSyncStart + timing->h_sync_width;
+    Mode->HTotal = timing->h_active + timing->h_blanking;
+    
+    Mode->VDisplay = timing->v_active;
+    Mode->VSyncStart = timing->v_active + timing->v_sync_off;
+    Mode->VSyncEnd = Mode->VSyncStart + timing->v_sync_width;
+    Mode->VTotal = timing->v_active + timing->v_blanking;
+    
+    /* We ignore h/v_size and h/v_border for now. */
+    
+    if (timing->interlaced)
+        Mode->Flags |= V_INTERLACE;
+    
+    if (timing->misc & 0x02)
+        Mode->Flags |= V_PHSYNC;
+    else
+        Mode->Flags |= V_NHSYNC;
+    
+    if (timing->misc & 0x01)
+        Mode->Flags |= V_PVSYNC;
+    else
+        Mode->Flags |= V_NVSYNC;
+ 
+    return Mode;
+}
 
-    if (makeEDID1prop) {
-      if ( (EDID1rawdata = xalloc(128*sizeof(CARD8)))==NULL ) {
-	return FALSE;
-      }
+/*
+ *
+ */
+static void
+DDCGuessRangesFromModes(int scrnIndex, MonPtr Monitor, DisplayModePtr Modes)
+{
+    DisplayModePtr Mode = Modes;
 
-      EDID1Atom = MakeAtom(EDID1_ATOM_NAME, sizeof(EDID1_ATOM_NAME), TRUE);
+    if (!Monitor || !Modes)
+        return;
 
+    /* set up the ranges for scanning through the modes */
+    Monitor->nHsync = 1;
+    Monitor->hsync[0].lo = 1024.0;
+    Monitor->hsync[0].hi = 0.0;
 
-      for (i=0; i<128; i++) {
-	EDID1rawdata[i] = DDC->rawData[i];
-      }
+    Monitor->nVrefresh = 1;
+    Monitor->vrefresh[0].lo = 1024.0;
+    Monitor->vrefresh[0].hi = 0.0;
 
-#ifdef DEBUG
-      ErrorF("xf86RegisterRootWindowProperty %p(%d,%d,%d,%d,%d,%p)\n",
-	     xf86RegisterRootWindowProperty,
-	     pScrnInfo->scrnIndex,
-	     EDID1Atom, XA_INTEGER, 8,
-	     128, (unsigned char *)EDID1rawdata  );
-#endif
+    while (Mode) {
+        if (!Mode->HSync)
+            Mode->HSync = ((float) Mode->Clock ) / ((float) Mode->HTotal);
 
-      ret = xf86RegisterRootWindowProperty(pScrnInfo->scrnIndex,
-					   EDID1Atom, XA_INTEGER, 8, 
-					   128, (unsigned char *)EDID1rawdata
-					   );
-      if (ret != Success)
-      ErrorF("xf86RegisterRootWindowProperty returns %d\n", ret );
-    } 
-
-    if (makeEDID2prop) {
-      if ( (EDID2rawdata = xalloc(256*sizeof(CARD8)))==NULL ) {
-	return FALSE;
-      }
-      for (i=0; i<256; i++) {
-	EDID2rawdata[i] = DDC->rawData[i];
-      }
-
-      EDID2Atom = MakeAtom(EDID2_ATOM_NAME, sizeof(EDID2_ATOM_NAME), TRUE);
-
-#ifdef DEBUG
-      ErrorF("xf86RegisterRootWindowProperty %p(%d,%d,%d,%d,%d,%p)\n",
-	     xf86RegisterRootWindowProperty,
-	     pScrnInfo->scrnIndex,
-	     EDID2Atom, XA_INTEGER, 8,
-	     256, (unsigned char *)EDID2rawdata  );
-#endif
-      ret = xf86RegisterRootWindowProperty(pScrnInfo->scrnIndex,
-					   EDID2Atom, XA_INTEGER, 8, 
-					   256, (unsigned char *)EDID2rawdata
-					   );
-      if (ret != Success)
-      ErrorF("xf86RegisterRootWindowProperty returns %d\n", ret );
+        if (!Mode->VRefresh)
+            Mode->VRefresh = (1000.0 * ((float) Mode->Clock)) / 
+                ((float) (Mode->HTotal * Mode->VTotal));
+
+        if (Mode->HSync < Monitor->hsync[0].lo)
+            Monitor->hsync[0].lo = Mode->HSync;
+
+        if (Mode->HSync > Monitor->hsync[0].hi)
+            Monitor->hsync[0].hi = Mode->HSync;
+
+        if (Mode->VRefresh < Monitor->vrefresh[0].lo)
+            Monitor->vrefresh[0].lo = Mode->VRefresh;
+
+        if (Mode->VRefresh > Monitor->vrefresh[0].hi)
+            Monitor->vrefresh[0].hi = Mode->VRefresh;
+        
+        Mode = Mode->next;
     }
+}
 
-    if (DDC->vdif) {
-#define VDIF_DUMMY_STRING "setting dummy VDIF property - please insert correct values\n"
-#ifdef DEBUG
-      ErrorF("xf86RegisterRootWindowProperty %p(%d,%d,%d,%d,%d,%p)\n",
-	     xf86RegisterRootWindowProperty,
-	     pScrnInfo->scrnIndex,
-	     VDIFAtom, XA_STRING, 8,
-	     strlen(VDIF_DUMMY_STRING), VDIF_DUMMY_STRING 
-	     );
-#endif
+/*
+ * Fill out MonPtr with xf86MonPtr information.
+ */
+void
+xf86DDCMonitorSet(int scrnIndex, MonPtr Monitor, xf86MonPtr DDC)
+{
+    DisplayModePtr Modes = NULL, Mode;
+    int i;
+    
+    if (!Monitor || !DDC)
+        return;
 
+    Monitor->DDC = DDC;
 
-      VDIFAtom = MakeAtom(VDIF_ATOM_NAME, sizeof(VDIF_ATOM_NAME), TRUE);
+    if (DDC->features.gamma > 0.0) {
+        Monitor->gamma.red = DDC->features.gamma;
+        Monitor->gamma.green = DDC->features.gamma;
+        Monitor->gamma.blue = DDC->features.gamma;
+    }
+
+    Monitor->widthmm = 10 * DDC->features.hsize;
+    Monitor->heightmm = 10 * DDC->features.vsize;
+    
+    /* If this is a digital display, then we can use reduced blanking */
+    if (DDC->features.input_type) 
+        Monitor->reducedblanking = TRUE;
+    /* Allow the user to also enable this through config */
+
+    /* Add established timings */
+    Mode = DDCModesFromEstablished(scrnIndex, &DDC->timings1);
+    Modes = xf86ModesAdd(Modes, Mode);
+
+    /* Add standard timings */
+    Mode = DDCModesFromStandardTiming(scrnIndex, DDC->timings2);
+    Modes = xf86ModesAdd(Modes, Mode);
+
+    /* Go through the detailed monitor sections */
+    for (i = 0; i < DET_TIMINGS; i++)
+        switch (DDC->det_mon[i].type) {
+        case DS_RANGES:
+            if (Monitor->nHsync && Monitor->nVrefresh) {
+                xf86DrvMsg(scrnIndex, X_INFO, "Ignoring EDID Ranges. Using"
+                           " configured ranges.\n");
+                break;
+            }
+
+            xf86DrvMsg(scrnIndex, X_INFO, "Using EDID ranges info for Monitor"
+                       " timing.\n");
+            Monitor->nHsync = 1;
+            Monitor->hsync[0].lo = DDC->det_mon[i].section.ranges.min_h;
+            Monitor->hsync[0].hi = DDC->det_mon[i].section.ranges.max_h;
+            
+            Monitor->nVrefresh = 1;
+            Monitor->vrefresh[0].lo = DDC->det_mon[i].section.ranges.min_v;
+            Monitor->vrefresh[0].hi = DDC->det_mon[i].section.ranges.max_v;
+
+            break;
+        case DT:
+            Mode = DDCModeFromDetailedTiming(scrnIndex, 
+                                             &DDC->det_mon[i].section.d_timings);
+            Modes = xf86ModesAdd(Modes, Mode);
+            break;
+        case DS_STD_TIMINGS:
+            Mode = DDCModesFromStandardTiming(scrnIndex,
+                                             DDC->det_mon[i].section.std_t);
+            Modes = xf86ModesAdd(Modes, Mode);
+            break;
+        default:
+            break;
+        }
+
+    if (Modes) {
+        /* Print Modes */
+        xf86DrvMsg(scrnIndex, X_INFO, "Printing DDC gathered Modelines:\n");
+
+        Mode = Modes;
+        while (Mode) {
+            PrintModeline(scrnIndex, Mode);
+            Mode = Mode->next;
+        }
 
-      ret = xf86RegisterRootWindowProperty(pScrnInfo->scrnIndex,
-					   VDIFAtom, XA_STRING, 8, 
-					   strlen(VDIF_DUMMY_STRING),
-					   VDIF_DUMMY_STRING 
-					   );
-      if (ret != Success)
-      ErrorF("xf86RegisterRootWindowProperty returns %d\n", ret );
+        /* Do we still need ranges to be filled in? */
+        if (!Monitor->nHsync || !Monitor->nVrefresh)
+            DDCGuessRangesFromModes(scrnIndex, Monitor, Modes);
+
+        /* look for last Mode */
+        Mode = Modes;
+
+        while (Mode->next)
+            Mode = Mode->next;
+        
+        /* add to MonPtr */
+        if (Monitor->Modes) {
+            Monitor->Last->next = Modes;
+            Modes->prev = Monitor->Last;
+            Monitor->Last = Mode;
+        } else {
+            Monitor->Modes = Modes;
+            Monitor->Last = Mode;
+        }
     }
+}
+
+/*
+ * Empty shell that keeps most drivers happy.
+ */
+Bool
+xf86SetDDCproperties(ScrnInfoPtr pScrn, xf86MonPtr DDC)
+{
+    if (!pScrn || !pScrn->monitor || !DDC)
+        return FALSE;
+
+    xf86DDCMonitorSet(pScrn->scrnIndex, pScrn->monitor, DDC);
 
     return TRUE;
 }
diff --git a/hw/xfree86/ddc/xf86DDC.h b/hw/xfree86/ddc/xf86DDC.h
index fb1083606..5def97a81 100644
--- a/hw/xfree86/ddc/xf86DDC.h
+++ b/hw/xfree86/ddc/xf86DDC.h
@@ -47,6 +47,9 @@ extern xf86vdifPtr xf86InterpretVdif(
     CARD8 *c
 );
 
+extern void 
+xf86DDCMonitorSet(int scrnIndex, MonPtr Monitor, xf86MonPtr DDC);
+
 extern Bool xf86SetDDCproperties(
     ScrnInfoPtr pScreen,
     xf86MonPtr DDC