From e54222fb0df35c9738947a6757dde09bf361a576 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@centraldogma>
Date: Tue, 23 Aug 2011 05:33:51 +0200
Subject: [PATCH] implement vesa screenblanking (issue #36)

---
 sys/src/9/pc/devvga.c  |  11 ++++-
 sys/src/9/pc/vgavesa.c | 108 ++++++++++++++++++++++++++++++++++-------
 2 files changed, 100 insertions(+), 19 deletions(-)

diff --git a/sys/src/9/pc/devvga.c b/sys/src/9/pc/devvga.c
index f1ecba8e9..10875f450 100644
--- a/sys/src/9/pc/devvga.c
+++ b/sys/src/9/pc/devvga.c
@@ -277,8 +277,13 @@ vgactl(Cmdbuf *cb)
 		for(i = 0; vgadev[i]; i++){
 			if(strcmp(cb->f[1], vgadev[i]->name))
 				continue;
-			if(scr->dev && scr->dev->disable)
-				scr->dev->disable(scr);
+			if(scr->dev){
+				if(scr->dev->disable)
+					scr->dev->disable(scr);
+				scr->fill = nil;
+				scr->scroll = nil;
+				scr->blank = nil;
+			}
 			scr->dev = vgadev[i];
 			if(scr->dev->enable)
 				scr->dev->enable(scr);
@@ -352,6 +357,8 @@ vgactl(Cmdbuf *cb)
 			error("drawinit: no gscreen");
 		if(scr->dev && scr->dev->drawinit)
 			scr->dev->drawinit(scr);
+		hwblank = scr->blank != nil;
+		hwaccel = scr->scroll || scr->fill;
 		vgascreenwin(scr);
 		resetscreenimage();
 		cursoron(1);
diff --git a/sys/src/9/pc/vgavesa.c b/sys/src/9/pc/vgavesa.c
index c2ea65138..d6e899890 100644
--- a/sys/src/9/pc/vgavesa.c
+++ b/sys/src/9/pc/vgavesa.c
@@ -1,8 +1,5 @@
 /*
  * vga driver using just vesa bios to set up.
- *
- * note that setting hwaccel to zero will cause cursor ghosts to be
- * left behind.  hwaccel set non-zero repairs this.
  */
 #include "u.h"
 #include "../port/lib.h"
@@ -21,10 +18,18 @@
 
 enum {
 	Usesoftscreen = 1,
+
+	Cdisable = 0,
+	Cenable,
+	Cblank,
 };
 
 static void *hardscreen;
 static uchar modebuf[0x1000];
+static Chan *creg, *cmem;
+static QLock vesaq;
+static Rendez vesar;
+static int vesactl;
 
 #define WORD(p) ((p)[0] | ((p)[1]<<8))
 #define LONG(p) ((p)[0] | ((p)[1]<<8) | ((p)[2]<<16) | ((p)[3]<<24))
@@ -48,19 +53,15 @@ vbesetup(Ureg *u, int ax)
 static void
 vbecall(Ureg *u)
 {
-	Chan *creg, *cmem;
+	static QLock callq;
 	ulong pa;
 
-	cmem = namec("/dev/realmodemem", Aopen, ORDWR, 0);
+	eqlock(&callq);
 	if(waserror()){
-		cclose(cmem);
-		nexterror();
-	}
-	creg = namec("/dev/realmode", Aopen, ORDWR, 0);
-	if(waserror()){
-		cclose(creg);
+		qunlock(&callq);
 		nexterror();
 	}
+
 	pa = PADDR(RMBUF);
 	if(devtab[cmem->type]->write(cmem, modebuf, sizeof(modebuf), pa) != sizeof(modebuf))
 		error("write modebuf");
@@ -77,9 +78,7 @@ vbecall(Ureg *u)
 		error("read modebuf");
 
 	poperror();
-	cclose(creg);
-	poperror();
-	cclose(cmem);
+	qunlock(&callq);
 }
 
 static void
@@ -216,13 +215,88 @@ vesaflush(VGAscr *scr, Rectangle r)
 	}
 }
 
+static int
+vesadisabled(void *)
+{
+	return vesactl == Cdisable;
+}
+
+static void
+vesaproc(void*)
+{
+	Ureg u;
+
+	while(vesactl != Cdisable){
+		if(!waserror()){
+			sleep(&vesar, vesadisabled, nil);
+			vbesetup(&u, 0x4f10);
+			if(vesactl == Cblank)
+				u.bx = 0x0101;
+			else	
+				u.bx = 0x0001;
+			vbecall(&u);
+			poperror();
+		}
+	}
+	cclose(cmem);
+	cclose(creg);
+	cmem = creg = nil;
+	qunlock(&vesaq);
+
+	pexit("", 1);
+}
+
+static void
+vesaenable(VGAscr *)
+{
+	eqlock(&vesaq);
+	if(waserror()){
+		qunlock(&vesaq);
+		nexterror();
+	}
+	cmem = namec("/dev/realmodemem", Aopen, ORDWR, 0);
+	if(waserror()){
+		cclose(cmem);
+		cmem = nil;
+		nexterror();
+	}
+	creg = namec("/dev/realmode", Aopen, ORDWR, 0);
+	poperror();
+	poperror();
+
+	vesactl = Cenable;
+	kproc("vesa", vesaproc, nil);
+}
+
+static void
+vesadisable(VGAscr *)
+{
+	vesactl = Cdisable;
+	wakeup(&vesar);
+}
+
+static void
+vesablank(VGAscr *, int blank)
+{
+	if(vesactl != Cdisable){
+		vesactl = blank ? Cblank : Cenable;
+		wakeup(&vesar);
+	}
+}
+
+static void
+vesadrawinit(VGAscr *scr)
+{
+	scr->blank = vesablank;
+}
+
 VGAdev vgavesadev = {
 	"vesa",
-	0,
-	0,
+	vesaenable,
+	vesadisable,
 	0,
 	vesalinear,
-	0,
+	vesadrawinit,
 	0,
 	0,
 	0,