I didn't want the black on white console text to burn in my monitor, so
I tried to run screenblank, only to find that it didn't work on macppc
(ofb driver doesn't support the ioctls to turn the screen off and on).
So I did a bit of poking around and found some OpenFirmware methods
that'll turn the monitor off and on, at least on my G4 Dual Proc with
Radeon card... I have no idea if they're available on other machines, or
even on the G4 DP with Rage128 card.

However, if anyone's interested, they're named ddc2ci-monitor-off and
ddc2ci-monitor-on. Here's a patch that adds support for 'em to the ofb
driver:

Index: ofb.c
===================================================================
RCS file: /cvsroot/syssrc/sys/arch/macppc/dev/ofb.c,v
retrieving revision 1.17
diff -u -r1.17 ofb.c
--- ofb.c	2000/11/02 14:25:51	1.17
+++ ofb.c	2001/01/06 20:33:28
@@ -102,6 +102,8 @@
 static void ofb_common_init __P((int, struct ofb_devconfig *));
 static int ofb_getcmap __P((struct ofb_softc *, struct wsdisplay_cmap *));
 static int ofb_putcmap __P((struct ofb_softc *, struct wsdisplay_cmap *));
+static void ofb_blank __P((struct ofb_devconfig *));
+static void ofb_unblank __P((struct ofb_devconfig *));

 int
 ofbmatch(parent, match, aux)
@@ -322,6 +324,18 @@
 	case WSDISPLAYIO_PUTCMAP:
 		return ofb_putcmap(sc, (struct wsdisplay_cmap *)data);

+	case WSDISPLAYIO_SVIDEO:
+		if (*(u_int *)data == WSDISPLAYIO_VIDEO_OFF)
+			ofb_blank(dc);
+		else
+			ofb_unblank(dc);
+		return 0;
+
+	case WSDISPLAYIO_GVIDEO:
+		*(u_int *)data = dc->dc_blanked ?
+		    WSDISPLAYIO_VIDEO_OFF : WSDISPLAYIO_VIDEO_ON;
+		return 0;
+
 	/* XXX There are no way to know framebuffer pa from a user program. */
 	case GRFIOCGINFO:
 		gm = (void *)data;
@@ -544,4 +558,24 @@
 	}

 	return 0;
+}
+
+void
+ofb_blank(dc)
+	struct ofb_devconfig *dc;
+{
+	if (!dc->dc_blanked) {
+		dc->dc_blanked = 1;
+		OF_call_method_1("ddc2ci-monitor-off", dc->dc_ih, 0);
+	}
+}
+
+void
+ofb_unblank(dc)
+	struct ofb_devconfig *dc;
+{
+	if (dc->dc_blanked) {
+		dc->dc_blanked = 0;
+		OF_call_method_1("ddc2ci-monitor-on", dc->dc_ih, 0);
+	}
 }

Index: ofbvar.h
===================================================================
RCS file: /cvsroot/syssrc/sys/arch/macppc/dev/ofbvar.h,v
retrieving revision 1.3
diff -u -r1.3 ofbvar.h
--- ofbvar.h	2000/06/19 19:35:21	1.3
+++ ofbvar.h	2001/01/06 20:27:22
@@ -31,6 +31,7 @@
 	paddr_t	dc_paddr;		/* physcal address */
 	int	dc_node;		/* phandle of this node */
 	int	dc_ih;			/* ihandle of this node */
+	int	dc_blanked;		/* currently has video disabled */
 	struct rasops_info dc_ri;
 };

-- 
Name: Dave Huang     |   Mammal, mammal / their names are called /
INet: khym@bga.com   |   they raise a paw / the bat, the cat /
FurryMUCK: Dahan     |   dolphin and dog / koala bear and hog -- TMBG
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