diff --git a/src/add-ons/accelerants/matrox/GetDeviceInfo.c b/src/add-ons/accelerants/matrox/GetDeviceInfo.c
index b4c6dede20..75059841ae 100644
--- a/src/add-ons/accelerants/matrox/GetDeviceInfo.c
+++ b/src/add-ons/accelerants/matrox/GetDeviceInfo.c
@@ -1,7 +1,6 @@
 /*
-	Authors:
-	Mark Watson - 21/6/00,
-	Apsed
+	Author:
+	Rudolf Cornelissen 11/2004
 */
 
 #define MODULE_BIT 0x04000000
@@ -11,41 +10,46 @@
 /* Get some info about the device */
 status_t GET_ACCELERANT_DEVICE_INFO(accelerant_device_info * adi) 
 {
-	/*no info on version is provided, so presumably this is for my info*/
-	LOG(4,("DEVICE_INFO: version 0x%08x\n", adi->version));
-	
-	switch ((si->ps.secondary_head << 4)|si->ps.card_type)
+	LOG(4,("GET_ACCELERANT_DEVICE_INFO: returning info\n"));
+
+	/* no info on version is provided, so presumably this is for my info */
+	adi->version = 1;
+
+	sprintf(adi->name, "Matrox chipset");
+	switch (si->ps.card_type)
 	{
-	case 0x01:
-		sprintf(adi->name,"Matrox G400 Plain");
+	case MIL1:
+		sprintf(adi->chipset, "Millennium I");
 		break;
-	case 0x02:
-		sprintf(adi->name,"Matrox G400 MAX");
+	case MYST:
+		sprintf(adi->chipset, "Mystique");
 		break;
-	case 0x11:
-		sprintf(adi->name,"Matrox Dualhead G400 Plain");
+	case MIL2:
+		sprintf(adi->chipset, "Millennium II");
 		break;
-	case 0x12:
-		sprintf(adi->name,"Matrox Dualhead G400 MAX");
+	case G100:
+		sprintf(adi->chipset, "G100");
+		break;
+	case G200:
+		sprintf(adi->chipset, "G200");
+		break;
+	case G400:
+	case G400MAX:
+		sprintf(adi->chipset, "G400");
+		break;
+	case G450:
+		sprintf(adi->chipset, "G450");
+		break;
+	case G550:
+		sprintf(adi->chipset, "G550");
+		break;
+	default:
+		sprintf(adi->chipset, "unknown");
 		break;
 	}
-	
-	sprintf(adi->chipset,"MGAG400");
-
-	sprintf(adi->serial_no,"01134"); /*FIXME*/
-
-	adi->memory=si->ps.memory_size * 1024 * 1024;
-	
-	adi->dac_speed=si->ps.max_dac1_clock;
-
-	// apsed, TODO ?? GET_ACCELERANT_DEVICE_INFO never called and kind of cards
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s 0x%08x %d\n", "version", adi->version, adi->version));
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s %s\n", "name", adi->name));
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s %s\n", "chipset", adi->chipset));
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s %s\n", "serial_no", adi->serial_no));
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s 0x%08x %d\n", "memory", adi->memory, adi->memory));
-	LOG(2,("GET_ACCELERANT_DEVICE_INFO %20s %d\n", "dac_speed", adi->dac_speed));
-
+	sprintf(adi->serial_no, "unknown");
+	adi->memory = (si->ps.memory_size * 1024 * 1024);
+	adi->dac_speed = si->ps.max_dac1_clock;
 
 	return B_OK;
 }
diff --git a/src/add-ons/accelerants/matrox/GetTimingConstraints.c b/src/add-ons/accelerants/matrox/GetTimingConstraints.c
index 29751b96c8..7e34855c44 100644
--- a/src/add-ons/accelerants/matrox/GetTimingConstraints.c
+++ b/src/add-ons/accelerants/matrox/GetTimingConstraints.c
@@ -1,7 +1,6 @@
 /*
-	Authors:
-	Mark Watson - 21/6/00,
-	Apsed
+	Author:
+	Rudolf Cornelissen 11/2004
 */
 
 #define MODULE_BIT 0x01000000
@@ -11,20 +10,25 @@
 /* Used to help generate mode lines */
 status_t GET_TIMING_CONSTRAINTS(display_timing_constraints * dtc) 
 {
-	// apsed, TODO, is that following card capabilities ?? 
-	LOG(4, ("GET_TIMING_CONSTRAINTS\n"));
-	
-	dtc->h_res=8;
-	dtc->h_sync_min=8;
-	dtc->h_sync_max=248;
-	dtc->h_blank_min=8;
-	dtc->h_blank_max=504;
-	
-	dtc->v_res=1;
-	dtc->v_sync_min=1;
-	dtc->v_sync_max=15;
-	dtc->v_blank_min=1;
-	dtc->v_blank_max=255;
+	LOG(4, ("GET_TIMING_CONSTRAINTS: returning info\n"));
+
+	/* specs are identical for all Matrox cards on CRTC1 (Mil-1 - G550) */
+	/* Note: G400-G550 CRTC2 have wider constraints, so this is OK. */
+	dtc->h_res = 8;
+	dtc->h_sync_min = 8;
+	dtc->h_sync_max = 248;
+	/* Note:
+	 * h_blank info is used to determine the max. diff. between h_total and h_display! */
+	dtc->h_blank_min = 8;
+	dtc->h_blank_max = 1016;
+
+	dtc->v_res = 1;
+	dtc->v_sync_min = 1;
+	dtc->v_sync_max = 15;
+	/* Note:
+	 * v_blank info is used to determine the max. diff. between v_total and v_display! */
+	dtc->v_blank_min = 1;
+	dtc->v_blank_max = 255;
 
 	return B_OK;
 }
diff --git a/src/add-ons/accelerants/matrox/engine/mga_crtc.c b/src/add-ons/accelerants/matrox/engine/mga_crtc.c
index 217268dbee..2e971f11d8 100644
--- a/src/add-ons/accelerants/matrox/engine/mga_crtc.c
+++ b/src/add-ons/accelerants/matrox/engine/mga_crtc.c
@@ -2,7 +2,7 @@
 /* Authors:
    Mark Watson 2/2000,
    Apsed,
-   Rudolf Cornelissen 11/2002-2/2004
+   Rudolf Cornelissen 11/2002-11/2004
 */
 
 #define MODULE_BIT 0x00040000
@@ -50,6 +50,9 @@ status_t gx00_crtc_validate_timing(
 	/* if hor. total does not leave room for a sensible sync pulse, increase it! */
 	if (*ht < (*hd_e + 80)) *ht = (*hd_e + 80);
 
+	/* if hor. total does not adhere to max. blanking pulse width, decrease it! */
+	if (*ht > (*hd_e + 0x3f8)) *ht = (*hd_e + 0x3f8);
+
 	/* make sure sync pulse is not during display */
 	if (*hs_e > (*ht - 8)) *hs_e = (*ht - 8);
 	if (*hs_s < (*hd_e + 8)) *hs_s = (*hd_e + 8);
@@ -86,6 +89,9 @@ status_t gx00_crtc_validate_timing(
 	/*if vertical total does not leave room for a sync pulse, increase it!*/
 	if (*vt < (*vd_e + 3)) *vt = (*vd_e + 3);
 
+	/* if vert. total does not adhere to max. blanking pulse width, decrease it! */
+	if (*vt > (*vd_e + 0xff)) *vt = (*vd_e + 0xff);
+
 	/* make sure sync pulse is not during display */
 	if (*vs_e > (*vt - 1)) *vs_e = (*vt - 1);
 	if (*vs_s < (*vd_e + 1)) *vs_s = (*vd_e + 1);