deal with some strange vesa modes.  

Reference: /n/atom/patch/applied/vesanotsquare
Date: Thu Apr 30 15:15:15 CES 2015
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/aux/vga/main.c	Thu Apr 30 15:14:55 2015
+++ /sys/src/cmd/aux/vga/main.c	Thu Apr 30 15:14:56 2015
@@ -163,6 +163,7 @@
 	Vga *vga;
 
 	fmtinstall('H', encodefmt);
+	quotefmtinstall();
 	Binit(&stdout, 1, OWRITE);
 
 	bios = getenv("vgactlr");
--- /sys/src/cmd/aux/vga/error.c	Thu Apr 30 15:14:58 2015
+++ /sys/src/cmd/aux/vga/error.c	Thu Apr 30 15:14:59 2015
@@ -15,7 +15,7 @@
 	int n;
 
 	sequencer(0, 1);
-	n = sprint(buf, "%s: ", argv0);
+	n = snprint(buf, sizeof buf, "%s: ", argv0);
 	va_start(arg, format);
 	out = vseprint(buf+n, buf+sizeof(buf)-n, format, arg);
 	va_end(arg);
--- /sys/src/cmd/aux/vga/vesa.c	Thu Apr 30 15:15:02 2015
+++ /sys/src/cmd/aux/vga/vesa.c	Thu Apr 30 15:15:03 2015
@@ -27,8 +27,10 @@
 	int	memfd;	/* /dev/realmem */
 	uchar	*mem;	/* copy of memory; 1MB */
 	uchar	*isvalid;	/* 1byte per 4kB in mem */
-	uchar	*buf;
 	uchar	*modebuf;
+	int	dspcon;	/* connected displays bitmask */
+	int	dspact;	/* active displays bitmask */
+	void (*scale)(Vga*, Ctlr*);
 };
 
 struct Vmode
@@ -93,6 +95,8 @@
 static Vbe *vbe;
 static Edid edid;
 
+extern Mode *vesamodes[];
+
 Vbe *mkvbe(void);
 int vbecheck(Vbe*);
 uchar *vbemodes(Vbe*);
@@ -105,14 +109,21 @@
 void vesaddc(void);
 int vbeddcedid(Vbe *vbe, Edid *e);
 void printedid(Edid*);
+int setdisplay(Vbe *vbe, int display);
+int getdisplay(Vbe *vbe);
+void fixbios(Vbe*);
+uchar* vbesetup(Vbe*, Ureg*, int);
+int vbecall(Vbe*, Ureg*);
 
 int
 dbvesa(Vga* vga)
 {
-	vbe = mkvbe();
 	if(vbe == nil){
-		fprint(2, "mkvbe: %r\n");
-		return 0;
+		vbe = mkvbe();
+		if(vbe == nil){
+			fprint(2, "mkvbe: %r\n");
+			return 0;
+		}
 	}
 	if(vbecheck(vbe) < 0){
 		fprint(2, "dbvesa: %r\n");
@@ -130,76 +141,183 @@
 	return 1;
 }
 
+static void
+addattr(Mode *m, char *attr, char *val)
+{
+	Attr *a;
+
+	a = alloc(sizeof(*a));
+	a->attr = attr;
+	a->val = val;
+	a->next = m->attr;
+	m->attr = a;
+}
+
 Mode*
-dbvesamode(char *mode)
+edidmode(Vmode *vm)
+{
+	Mode *m;
+	Modelist *l;
+
+	for(l = edid.modelist; l != nil; l = l->next){
+		if(l->x != vm->dx || l->y != vm->dy)
+			continue;
+		m = l;
+		return m;
+	}
+	return nil;
+}
+
+Mode*
+vesamode0(Vmode *vm)
 {
 	int i;
+	static Mode m;
+
+	for(i=0; vesamodes[i] != nil; i++){
+		if(vesamodes[i]->x != vm->dx || vesamodes[i]->y != vm->dy)
+			continue;
+		return vesamodes[i];
+	}
+	m.x = vm->dx;
+	m.y = vm->dy;
+	m.ht = m.x;
+	m.shb = m.x;
+	m.ehb = m.x;
+	m.shs = m.x;
+	m.ehs = m.x;
+	m.vt = m.y;
+	m.vrs = m.y;
+	m.vre = m.y;
+	m.frequency = m.ht * m.vt * 60;
+	return &m;
+}
+
+Mode*
+mkmode(Vmode *vm, char *scale, int display)
+{
+	int width;
+	Mode *m, *v, *e;
+
+	e = edidmode(vm);
+	if(e == nil && edid.modelist != nil){
+		fprint(2, "dbvesamode: mode %dx%dx0 not in edid info\n", vm->dx, vm->dy);
+		return nil;
+	}
+	v = vesamode0(vm);
+	if(v == nil){
+		fprint(2, "dbvesamode: mode %dx%dx0 not in vesa info\n", vm->dx, vm->dy);
+		return nil;
+	}
+	if(e != nil && v != nil && (e->x != v->x || e->y != v->y)){
+		fprint(2, "dbvesamode: mode %dx%dx0 !~ %dx%dx%d not in vesa info",
+			e->x, e->y, v->x, v->y, vm->depth);
+		return nil;
+	}
+
+	m = alloc(sizeof *m);
+	if(e != nil)
+		*m = *e;
+	else
+		*m = *v;
+
+	strcpy(m->type, "vesa");
+	strcpy(m->size, vm->name);
+	strcpy(m->chan, vm->chan);
+	m->z = vm->depth;
+
+	addattr(m, "id", smprint("%#x", vm->id));
+	if(scale != nil)
+		addattr(m, "scale", smprint("%s", scale));
+	if(display != 0)
+		addattr(m, "display", smprint("%d", display));
+	if((width = vm->bpl * 8 / m->z) > m->x)
+		addattr(m, "virtx", smprint("%d", width));
+
+	return m;
+}
+
+Mode*
+dbvesamode(char *mode)
+{
+	int i, n, display, oldmode, olddisplay;
 	uchar *p, *ep;
 	Vmode vm;
-	Mode *m;
-	
+	char *scale, *f[6];
+
 	if(vbe == nil)
 		return nil;
 
-	p = vbemodes(vbe);
-	if(p == nil)
-		return nil;
-	for(ep=p+1024; (p[0]!=0xFF || p[1]!=0xFF) && p<ep; p+=2){
-		if(vbemodeinfo(vbe, WORD(p), &vm) < 0)
-			continue;
-		if(strcmp(vm.name, mode) == 0)
-			goto havemode;
-	}
-	if(1){
+	display = 0;
+	oldmode = 0;
+	olddisplay = 0;
+	scale = nil;
+	n = gettokens(mode, f, nelem(f), ",");
+	for(i = 1; i < n; i++){
+		if(strncmp(f[i], "display=", 8) == 0)
+			display = atoi(f[i]+8);
+		else if(strncmp(f[i], "scale=", 6) == 0)
+			scale = f[i]+6;
+		else
+			error("dbvesamode: unknown attribute: %q\n", f[i]);
+	}
+
+	if(display != 0){
+		olddisplay = getdisplay(vbe);
+		oldmode = vbegetmode(vbe);
+		if(setdisplay(vbe, display) < 0)
+			return nil;
+	}
+
+	if(strncmp(mode, "0x", 2) == 0){
+		if(vbemodeinfo(vbe, strtol(mode, nil, 0), &vm) == 0)
+			return mkmode(&vm, scale, display);
+	}else{
+		if(p = vbemodes(vbe)){
+			for(ep=p+1024; (p[0]!=0xFF || p[1]!=0xFF) && p<ep; p+=2){
+				if(vbemodeinfo(vbe, WORD(p), &vm) < 0)
+					continue;
+				if(strcmp(vm.name, mode) == 0)
+					return mkmode(&vm, scale, display);
+			}
+		}
 		fprint(2, "warning: scanning for unoffered vesa modes\n");
 		for(i=0x100; i<0x200; i++){
 			if(vbemodeinfo(vbe, i, &vm) < 0)
 				continue;
 			if(strcmp(vm.name, mode) == 0)
-				goto havemode;
-			/* accept mode numbers so we can select bit pattern */
-			if(vm.id == strtoul(mode, 0, 0))
-				goto havemode;
+				return mkmode(&vm, scale, display);
 		}
 	}
+	if(display != 0 && setdisplay(vbe, olddisplay) == 0)
+		vbesetmode(vbe, oldmode);
 	werrstr("no such vesa mode");
 	return nil;
-
-havemode:
-	m = alloc(sizeof(Mode));
-	strcpy(m->type, "vesa");
-	strcpy(m->size, vm.name);
-	strcpy(m->chan, vm.chan);
-	m->frequency = 100;
-	m->x = vm.dx;
-	m->y = vm.dy;
-	m->z = vm.depth;
-	m->ht = m->x;
-	m->shb = m->x;
-	m->ehb = m->x;
-	m->shs = m->x;
-	m->ehs = m->x;
-	m->vt = m->y;
-	m->vrs = m->y;
-	m->vre = m->y;
-
-	m->attr = alloc(sizeof(Attr));
-	m->attr->attr = "id";
-	m->attr->val = alloc(32);
-	sprint(m->attr->val, "0x%x", vm.id);
-	return m;
 }
 
 static void
 snarf(Vga* vga, Ctlr* ctlr)
 {
-	if(!vbe)
+	if(vbe == nil)
 		vbe = mkvbe();
-	if(vbe)
+	if(vbe != nil)
 		vga->vesa = ctlr;
 	vbesnarf(vbe, vga);
 	vga->linear = 1;
-	ctlr->flag |= Hlinear|Ulinear;
+	ctlr->flag |= Hlinear|Ulinear|Fsnarf;
+}
+
+static void
+options(Vga *vga, Ctlr *ctlr)
+{
+	char *v;
+
+	if(v = dbattr(vga->mode->attr, "virtx")){
+		vga->virtx = atoi(v);
+		vga->virty = vga->mode->y;
+		vga->panning = 0;
+	}
+	ctlr->flag |= Foptions;
 }
 
 static void
@@ -210,7 +328,8 @@
 	if(vbesetmode(vbe, atoi(dbattr(vga->mode->attr, "id"))) < 0){
 		ctlr->flag |= Ferror;
 		fprint(2, "vbesetmode: %r\n");
-	}
+	}else if(vbe->scale != nil)
+		vbe->scale(vga, ctlr);
 }
 
 static void
@@ -220,7 +339,7 @@
 	char did[0x200];
 	uchar *p, *ep;
 
-	if(!vbe){
+	if(vbe == nil){
 		Bprint(&stdout, "no vesa bios\n");
 		return;
 	}
@@ -228,7 +347,7 @@
 	memset(did, 0, sizeof did);
 	vbeprintinfo(vbe);
 	p = vbemodes(vbe);
-	if(p){
+	if(p != nil){
 		for(ep=p+1024; (p[0]!=0xFF || p[1]!=0xFF) && p<ep; p+=2){
 			vbeprintmodeinfo(vbe, WORD(p), "");
 			if(WORD(p) < nelem(did))
@@ -246,11 +365,71 @@
 		printedid(&edid);
 }
 
+static void
+intelscale(Vga* vga, Ctlr* ctlr)
+{
+	Ureg u;
+	int cx;
+	char *scale;
+
+	if(vbe == nil)
+		error("no vesa bios\n");
+
+	/* NOTE: intel doesn't support "aspect" scaling mode :( */
+	scale = dbattr(vga->mode->attr, "scale");
+	if(scale == nil)
+		cx = 0;
+	else if(strcmp(scale, "scalefull") == 0)
+		cx = 4;
+	else{
+		ctlr->flag |= Ferror;
+		fprint(2, "vbescale: unsupported mode %s\n", scale);
+		return;
+	}
+
+	vbesetup(vbe, &u, 0x5F61);
+	u.bx = 0;
+	u.cx = cx; /* horizontal */
+	u.dx = cx; /* vertical */
+	if(vbecall(vbe, &u) < 0 && (u.ax&0xFFFF) != 0x5F)
+		fprint(2, "vbescale: %r\n");
+}
+
+static void
+nvidiascale(Vga* vga, Ctlr* ctlr)
+{
+	Ureg u;
+	int cx;
+	char *scale;
+
+	if(vbe == nil)
+		error("no vesa bios\n");
+
+	scale = dbattr(vga->mode->attr, "scale");
+	if(scale == nil)
+		cx = 1;
+	else if(strcmp(scale, "scaleaspect") == 0)
+		cx = 3;
+	else if(strcmp(scale, "scalefull") == 0)
+		cx = 0;
+	else{
+		ctlr->flag |= Ferror;
+		fprint(2, "vbescale: unsupported mode %s\n", scale);
+		return;
+	}
+
+	vbesetup(vbe, &u, 0x4F14);
+	u.bx = 0x102;
+	u.cx = cx;
+	if(vbecall(vbe, &u) < 0)
+		fprint(2, "vbescale: %r\n");
+}
+
 Ctlr vesa = {
 	"vesa",			/* name */
 	snarf,				/* snarf */
-	0,			/* options */
-	0,				/* init */
+	options,			/* options */
+	nil,				/* init */
 	load,				/* load */
 	dump,				/* dump */
 };
@@ -278,19 +457,36 @@
 	0
 };
 
+enum {
+	AttrSupported	= 1<<0,
+	AttrTTY		= 1<<2,
+	AttrColor	= 1<<3,
+	AttrGraphics	= 1<<4,
+	AttrNotVGA	= 1<<5,
+	AttrNotWinVGA	= 1<<6,
+	AttrLinear	= 1<<7,
+	AttrDoublescan	= 1<<8,
+	AttrInterlace	= 1<<9,
+	AttrTriplebuf	= 1<<10,
+	AttrStereo	= 1<<11,
+	AttrDualAddr	= 1<<12,
+
+	AttrRequired	= AttrSupported | AttrGraphics | AttrLinear,
+};
+
 static Flag modeattributesflags[] = {
-	1<<0, "supported",
-	1<<2, "tty",
-	1<<3, "color",
-	1<<4, "graphics",
-	1<<5, "not-vga",
-	1<<6, "no-windowed-vga",
-	1<<7, "linear",
-	1<<8, "double-scan",
-	1<<9, "interlace",
-	1<<10, "triple-buffer",
-	1<<11, "stereoscopic",
-	1<<12, "dual-start-addr",
+	AttrSupported,	"supported",
+	AttrTTY,	"tty",
+	AttrColor,	"color",
+	AttrGraphics,	"graphics",
+	AttrNotVGA,	"not-vga",
+	AttrNotWinVGA,	"no-windowed-vga",
+	AttrLinear,	"linear",
+	AttrDoublescan,	"double-scan",
+	AttrInterlace,	"interlace",
+	AttrTriplebuf,	"triple-buffer",
+	AttrStereo,	"stereoscopic",
+	AttrDualAddr,	"dual-start-addr",
 	0
 };
 
@@ -307,8 +503,26 @@
 	0
 };
 
+enum {
+	ModText = 0,
+	ModCGA,
+	ModHercules,
+	ModPlanar,
+	ModPacked,
+	ModNonChain4,
+	ModDirect,
+	ModYUV,
+};
+
 static char *modelstr[] = {
-	"text", "cga", "hercules", "planar", "packed", "non-chain4", "direct", "YUV"
+	[ModText]	"text",
+	[ModCGA]	"cga",
+	[ModHercules]	"hercules",
+	[ModPlanar]	"planar",
+	[ModPacked]	"packed",
+	[ModNonChain4]	"non-chain4",
+	[ModDirect]	"direct",
+	[ModYUV]	"YUV",
 };
 
 static void
@@ -334,72 +548,104 @@
 		return nil;
 	vbe->mem = alloc(MemSize);
 	vbe->isvalid = alloc(MemSize/PageSize);
-	vbe->buf = alloc(PageSize);
 	vbe->modebuf = alloc(PageSize);
+	fixbios(vbe);
 	return vbe;
 }
 
 static void
-loadpage(Vbe *vbe, int p)
+loadpage(Vbe *vbe, int p, int wr)
+{
+	if(p >= MemSize/PageSize)
+		return;
+	if(vbe->isvalid[p] == 0)
+		if(pread(vbe->memfd, vbe->mem+p*PageSize, PageSize, p*PageSize) != PageSize)
+			error("read /dev/realmodemem: %r\n");
+	vbe->isvalid[p] = 1+wr;
+}
+
+static void
+flushpage(Vbe *vbe, int p)
 {
-	if(p >= MemSize/PageSize || vbe->isvalid[p])
+	if(p >= MemSize/PageSize || vbe->isvalid[p]!=2)
 		return;
-	if(pread(vbe->memfd, vbe->mem+p*PageSize, PageSize, p*PageSize) != PageSize)
-		error("read /dev/realmodemem: %r\n");
+	if(pwrite(vbe->memfd, vbe->mem+p*PageSize, PageSize, p*PageSize) != PageSize)
+		error("write /dev/realmodemem: %r\n");
 	vbe->isvalid[p] = 1;
 }
 
 static void*
+getmem(Vbe *vbe, int off, int wr)
+{
+	if(off == 0 || off >= MemSize)
+		return nil;
+	loadpage(vbe, off/PageSize, wr);
+	if(off % PageSize)
+		loadpage(vbe, (off/PageSize)+1, wr);
+	return vbe->mem+off;
+}
+
+static void*
 unfarptr(Vbe *vbe, uchar *p)
 {
 	int seg, off;
 
 	seg = WORD(p+2);
 	off = WORD(p);
-	if(seg==0 && off==0)
-		return nil;
 	off += seg<<4;
-	if(off >= MemSize)
-		return nil;
-	loadpage(vbe, off/PageSize);
-	loadpage(vbe, off/PageSize+1);	/* just in case */
-	return vbe->mem+off;
+	return getmem(vbe, off, 0);
 }
 
 uchar*
 vbesetup(Vbe *vbe, Ureg *u, int ax)
 {
-	memset(vbe->buf, 0, PageSize);
+	uchar *p;
+
 	memset(u, 0, sizeof *u);
 	u->ax = ax;
 	u->es = (RealModeBuf>>4)&0xF000;
 	u->di = RealModeBuf&0xFFFF;
-	return vbe->buf;
+	p = getmem(vbe, RealModeBuf, 1);
+	memset(p, 0, PageSize);
+	return p;
+}
+
+void
+vbeflush(Vbe *vbe)
+{
+	int p;
+
+	for(p=0; p<MemSize/PageSize; p++)
+		flushpage(vbe, p);
+
+	memset(vbe->isvalid, 0, MemSize/PageSize);
 }
 
 int
 vbecall(Vbe *vbe, Ureg *u)
 {
 	u->trap = 0x10;
-	if(pwrite(vbe->memfd, vbe->buf, PageSize, RealModeBuf) != PageSize)
-		error("write /dev/realmodemem: %r\n");
+
+	vbeflush(vbe);
+
 	if(pwrite(vbe->rmfd, u, sizeof *u, 0) != sizeof *u)
 		error("write /dev/realmode: %r\n");
 	if(pread(vbe->rmfd, u, sizeof *u, 0) != sizeof *u)
 		error("read /dev/realmode: %r\n");
-	if(pread(vbe->memfd, vbe->buf, PageSize, RealModeBuf) != PageSize)
-		error("read /dev/realmodemem: %r\n");
+
+	getmem(vbe, RealModeBuf, 0);
+
 	if((u->ax&0xFFFF) != 0x004F){
 		werrstr("VBE error %#.4lux", u->ax&0xFFFF);
 		return -1;
 	}
-	memset(vbe->isvalid, 0, MemSize/PageSize);
 	return 0;
 }
 
 int
 vbecheck(Vbe *vbe)
 {
+	char *oem;
 	uchar *p;
 	Ureg u;
 
@@ -411,6 +657,23 @@
 		werrstr("invalid vesa signature %.4H %.4H\n", p, p+4);
 		return -1;
 	}
+	oem = unfarptr(vbe, p+6);
+	if(strncmp(oem, "Intel", 5) == 0){
+		vbe->scale = intelscale;
+
+		/* detect connected display devices */
+		vbesetup(vbe, &u, 0x5F64);
+		u.bx = 0x200;
+		vbecall(vbe, &u);
+		vbe->dspcon = u.cx >> 8; /* CH = connected, CL = available? */
+
+		/* detect active display devices */
+		vbesetup(vbe, &u, 0x5F64);
+		u.bx = 0x100;
+		vbecall(vbe, &u);
+		vbe->dspact = u.cx;
+	}else if(memcmp(oem, "NVIDIA", 6) == 0)
+		vbe->scale = nvidiascale;
 	return 0;
 }
 
@@ -427,6 +690,7 @@
 	if(memcmp(p, "VESA", 4) != 0 || p[5] < 2)
 		return -1;
 	vga->apz = WORD(p+18)*0x10000UL;
+	vbeddcedid(vbe, &edid);
 	return 0;
 }
 
@@ -434,6 +698,7 @@
 vbeprintinfo(Vbe *vbe)
 {
 	uchar *p;
+	int i;
 	Ureg u;
 
 	p = vbesetup(vbe, &u, 0x4F00);
@@ -460,6 +725,18 @@
 
 	printitem("vesa", "mem");
 	Bprint(&stdout, "%lud\n", WORD(p+18)*0x10000UL);
+
+	printitem("vesa", "dsp con");
+	for(i = 0; i < 8; i++)
+		if(vbe->dspcon & (1<<i))
+			Bprint(&stdout, "%d ", i+1);
+	Bprint(&stdout, "\n");
+
+	printitem("vesa", "dsp act");
+	for(i = 0; i < 8; i++)
+		if(vbe->dspact & (1<<i))
+			Bprint(&stdout, "%d ", i+1);
+	Bprint(&stdout, "\n");
 }
 
 uchar*
@@ -479,7 +756,7 @@
 int
 vbemodeinfo(Vbe *vbe, int id, Vmode *m)
 {
-	int o;
+	int o, mod;
 	ulong d, c, x;
 	uchar *p;
 	char tmp[sizeof m->chan];
@@ -496,7 +773,23 @@
 	m->dx = WORD(p+18);
 	m->dy = WORD(p+20);
 	m->depth = p[25];
-	m->model = p[27] < nelem(modelstr) ? modelstr[p[27]] : "unknown";
+	if((m->attr & AttrRequired) != AttrRequired
+	|| m->dx * m->dy * m->depth < 0 || m->bpl <= 0){
+		werrstr("mode unsupported");
+		return -1;
+	}
+	mod = p[27];
+	switch(mod){
+	default:
+		werrstr("mode unsupported");
+		return -1;
+	case ModCGA:
+	case ModHercules:
+	case ModPacked:
+	case ModDirect:
+		m->model = modelstr[mod];
+		break;
+	}
 	m->r = p[31];
 	m->g = p[33];
 	m->b = p[35];
@@ -510,7 +803,8 @@
 	snprint(m->name, sizeof m->name, "%dx%dx%d",
 		m->dx, m->dy, m->depth);
 	if(m->depth <= 8) {
-		snprint(m->chan, sizeof m->chan, "m%d", m->depth);
+		snprint(m->chan, sizeof m->chan, "%c%d", 
+			(m->attr & AttrColor) ? 'm' : 'k', m->depth);
 		return 0;
 	}
 
@@ -612,7 +906,7 @@
 {
 	if(vbe == nil){
 		vbe = mkvbe();
-		if(!vbe)
+		if(vbe == nil)
 			error("mkvbe: %r\n");
 	}
 	if(vbecheck(vbe) < 0)
@@ -638,7 +932,7 @@
 {
 	uchar *p;
 	Ureg u;
-	
+
 	p = vbesetup(vbe, &u, 0x4F15);
 	u.bx = 0x0001;
 	if(vbecall(vbe, &u) < 0)
@@ -649,12 +943,12 @@
 	}
 	return 0;
 }
-	
+
 void
 printedid(Edid *e)
 {
 	Modelist *l;
-	
+
 	printitem("edid", "mfr");
 	Bprint(&stdout, "%s\n", e->mfr);
 	printitem("edid", "serialstr");
@@ -681,7 +975,7 @@
 	Bprint(&stdout, "%lud\n", e->pclkmax);
 	printitem("edid", "flags");
 	printflags(edidflags, e->flags);
-	
+
 	for(l=e->modelist; l; l=l->next){
 		printitem("edid", l->name);
 		Bprint(&stdout, "\n\t\tclock=%g\n\t\tshb=%d ehb=%d ht=%d\n\t\tvrs=%d vre=%d vt=%d\n\t\thsync=%c vsync=%c %s\n",
@@ -695,7 +989,6 @@
 	int rr;
 	Modelist **lp;
 
-//m.z = 8; // BUG
 	rr = (m.frequency+m.ht*m.vt/2)/(m.ht*m.vt);
 	snprint(m.name, sizeof m.name, "%dx%dx%d@%dHz", m.x, m.y, m.z, rr);
 
@@ -837,8 +1130,6 @@
 	return 0;
 }
 
-extern Mode *vesamodes[];
-
 int
 vesalookup(Mode *m, char *name)
 {
@@ -982,7 +1273,7 @@
 	 */
 	estab = (p[0]<<16) | (p[1]<<8) | p[2];
 	p += 3;
-	
+
 	for(i=0, m=1<<23; i<nelem(estabtime); i++, m>>=1)
 		if(estab & m)
 			if(vesalookup(&mode, estabtime[i]) == 0)
@@ -1001,9 +1292,7 @@
 	/*
 	 * Detailed Timings
 	 */
-fprint(2, "dt\n");
 	for(i=0; i<4; i++, p+=18) {
-fprint(2, "%.8H\n", p);
 		if(p[0] || p[1]) {	/* detailed timing block: p[0] or p[1] != 0 */
 			if(decodedtb(&mode, p) == 0)
 				e->modelist = addmode(e->modelist, mode);
@@ -1018,7 +1307,6 @@
 			case 0xFE:	/* ascii string (13-byte ascii, 0A terminated) */
 				break;
 			case 0xFD:	/* monitor range limits */
-				print("fd %.18H\n", p);
 				e->rrmin = p[5];
 				e->rrmax = p[6];
 				e->hrmin = p[7]*1000;
@@ -1045,4 +1333,73 @@
 
 	assert(p == (uchar*)v+8+10+2+5+10+3+16+72);
 	return 0;
+}
+
+int
+getdisplay(Vbe *vbe)
+{
+	int i;
+
+	for(i = 0; i < 8; i++)
+		if(vbe->dspact & 1<<i)
+			return i+1;
+
+	/* fallback to a connected one */
+	for(i = 0; i < 8; i++)
+		if(vbe->dspcon & 1<<i)
+			return i+1;
+
+	return 0;
+}
+
+int
+setdisplay(Vbe *vbe, int display)
+{
+	Ureg u;
+	int cx;
+
+	if(display == 0)
+		return 0;
+
+	cx = 1<<(display-1);
+	if(vbe->dspcon & cx){
+		/* switch to common mode before trying */
+		vbesetmode(vbe, 3);
+
+		vbesetup(vbe, &u, 0x5F64);
+		u.bx = 0;
+		u.cx = cx;
+		vbecall(vbe, &u);
+		if(u.ax == 0x5f)
+			return 0;
+		werrstr("setdisplay: VBE error %#.4lux", u.ax);
+	}else
+		werrstr("setdisplay: %d not connected", display);
+	return -1;
+}
+
+void
+fixbios(Vbe *vbe)
+{
+	uchar *p;
+	int i;
+
+	/*
+	 * Intel(r) Cantiga Graphics Chip Accelerated VGA BIOS 1.0 has
+	 * a wrong entry in mode alias table at c000:7921 for mode 0x16b 
+	 * (1440x900x32) wrongly replacing it with mode 0x162 (768x480x32).
+	 */
+	p = getmem(vbe, 0xc7921, 0);
+	if(p != nil && p[0] == 0x01 && p[1] == 0xff && p[2] == 0xff){
+		for(i=1; i<64; i++){
+			p = getmem(vbe, 0xc7921 + 3*i, 0);
+			if(p == nil || p[0] == 0xff)
+				break;
+			if(p[0] == 0x6b && p[1] == 0x6b && p[2] == 0x62){
+				p = getmem(vbe, 0xc7921 + 3*i, 1);
+				p[2] = 0x6b;	/* fix */
+				break;
+			}
+		}
+	}
 }