Import sources from 2011-03-30 iso image

1 files changed, 1043 insertions, 0 deletions

diff --git a/sys/src/cmd/aux/vga/vesa.c b/sys/src/cmd/aux/vga/vesa.c
new file mode 100755
index 000000000..4a4c362b8
--- /dev/null
+++ b/sys/src/cmd/aux/vga/vesa.c
@@ -0,0 +1,1043 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include </386/include/ureg.h>
+typedef struct Ureg Ureg;
+
+#include "pci.h"
+#include "vga.h"
+
+typedef struct Vbe Vbe;
+typedef struct Vmode Vmode;
+typedef struct Modelist Modelist;
+typedef struct Edid Edid;
+
+enum
+{
+	MemSize = 1024*1024,
+	PageSize = 4096,
+	RealModeBuf = 0x9000,
+};
+
+struct Vbe
+{
+	int	rmfd;	/* /dev/realmode */
+	int	memfd;	/* /dev/realmem */
+	uchar	*mem;	/* copy of memory; 1MB */
+	uchar	*isvalid;	/* 1byte per 4kB in mem */
+	uchar	*buf;
+	uchar	*modebuf;
+};
+
+struct Vmode
+{
+	char	name[32];
+	char	chan[32];
+	int	id;
+	int	attr;	/* flags */
+	int	bpl;
+	int	dx, dy;
+	int	depth;
+	char	*model;
+	int	r, g, b, x;
+	int	ro, go, bo, xo;
+	int	directcolor;	/* flags */
+	ulong	paddr;
+};
+
+struct Edid {
+	char		mfr[4];		/* manufacturer */
+	char		serialstr[16];	/* serial number as string (in extended data) */
+	char		name[16];		/* monitor name as string (in extended data) */
+	ushort	product;		/* product code, 0 = unused */
+	ulong	serial;		/* serial number, 0 = unused */
+	uchar	version;		/* major version number */
+	uchar	revision;		/* minor version number */
+	uchar	mfrweek;		/* week of manufacture, 0 = unused */
+	int		mfryear;		/* year of manufacture, 0 = unused */
+	uchar 	dxcm;		/* horizontal image size in cm. */
+	uchar	dycm;		/* vertical image size in cm. */
+	int		gamma;		/* gamma*100 */
+	int		rrmin;		/* minimum vertical refresh rate */
+	int		rrmax;		/* maximum vertical refresh rate */
+	int		hrmin;		/* minimum horizontal refresh rate */
+	int		hrmax;		/* maximum horizontal refresh rate */
+	ulong	pclkmax;		/* maximum pixel clock */
+	int		flags;
+
+	Modelist	*modelist;		/* list of supported modes */
+};
+
+struct Modelist
+{
+	Mode;
+	Modelist *next;
+};
+
+enum {
+	Fdigital = 1<<0,		/* is a digital display */
+	Fdpmsstandby = 1<<1,	/* supports DPMS standby mode */
+	Fdpmssuspend = 1<<2,	/* supports DPMS suspend mode */
+	Fdpmsactiveoff = 1<<3,	/* supports DPMS active off mode */
+	Fmonochrome = 1<<4,	/* is a monochrome display */
+	Fgtf = 1<<5,		/* supports VESA GTF: see /public/doc/vesa/gtf10.pdf */
+};
+
+#define WORD(p) ((p)[0] | ((p)[1]<<8))
+#define LONG(p) ((p)[0] | ((p)[1]<<8) | ((p)[2]<<16) | ((p)[3]<<24))
+#define PWORD(p, v) (p)[0] = (v); (p)[1] = (v)>>8
+#define PLONG(p, v) (p)[0] = (v); (p)[1] = (v)>>8; (p)[2] = (v)>>16; (p)[3] = (v)>>24
+
+static Vbe *vbe;
+static Edid edid;
+
+Vbe *mkvbe(void);
+int vbecheck(Vbe*);
+uchar *vbemodes(Vbe*);
+int vbemodeinfo(Vbe*, int, Vmode*);
+int vbegetmode(Vbe*);
+int vbesetmode(Vbe*, int);
+void vbeprintinfo(Vbe*);
+void vbeprintmodeinfo(Vbe*, int, char*);
+int vbesnarf(Vbe*, Vga*);
+void vesaddc(void);
+int vbeddcedid(Vbe *vbe, Edid *e);
+void printedid(Edid*);
+
+int
+dbvesa(Vga* vga)
+{
+	vbe = mkvbe();
+	if(vbe == nil){
+		fprint(2, "mkvbe: %r\n");
+		return 0;
+	}
+	if(vbecheck(vbe) < 0){
+		fprint(2, "dbvesa: %r\n");
+		return 0;
+	}
+	vga->link = alloc(sizeof(Ctlr));
+	*vga->link = vesa;
+	vga->vesa = vga->link;
+	vga->ctlr = vga->link;
+
+	vga->link->link = alloc(sizeof(Ctlr));
+	*vga->link->link = softhwgc;
+	vga->hwgc = vga->link->link;
+
+	return 1;
+}
+
+Mode*
+dbvesamode(char *mode)
+{
+	int i;
+	uchar *p, *ep;
+	Vmode vm;
+	Mode *m;
+	
+	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){
+		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;
+		}
+	}
+	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)
+		vbe = mkvbe();
+	if(vbe)
+		vga->vesa = ctlr;
+	vbesnarf(vbe, vga);
+	vga->linear = 1;
+	ctlr->flag |= Hlinear|Ulinear;
+}
+
+static void
+load(Vga* vga, Ctlr* ctlr)
+{
+	if(vbe == nil)
+		error("no vesa bios\n");
+	if(vbesetmode(vbe, atoi(dbattr(vga->mode->attr, "id"))) < 0){
+		ctlr->flag |= Ferror;
+		fprint(2, "vbesetmode: %r\n");
+	}
+}
+
+static void
+dump(Vga*, Ctlr*)
+{
+	int i;
+	char did[0x200];
+	uchar *p, *ep;
+
+	if(!vbe){
+		Bprint(&stdout, "no vesa bios\n");
+		return;
+	}
+
+	memset(did, 0, sizeof did);
+	vbeprintinfo(vbe);
+	p = vbemodes(vbe);
+	if(p){
+		for(ep=p+1024; (p[0]!=0xFF || p[1]!=0xFF) && p<ep; p+=2){
+			vbeprintmodeinfo(vbe, WORD(p), "");
+			if(WORD(p) < nelem(did))
+				did[WORD(p)] = 1;
+		}
+	}
+	for(i=0x100; i<0x1FF; i++)
+		if(!did[i])
+			vbeprintmodeinfo(vbe, i, " (unoffered)");
+				
+	
+	if(vbeddcedid(vbe, &edid) < 0)
+		fprint(2, "warning: reading edid: %r\n");
+	else
+		printedid(&edid);
+}
+
+Ctlr vesa = {
+	"vesa",			/* name */
+	snarf,				/* snarf */
+	0,			/* options */
+	0,				/* init */
+	load,				/* load */
+	dump,				/* dump */
+};
+
+Ctlr softhwgc = {
+	"soft",
+};
+
+/*
+ * VESA bios extension
+ */
+
+typedef struct Flag Flag;
+struct Flag {
+	int bit;
+	char *desc;
+};
+
+static Flag capabilityflag[] = {
+	0x01, "8-bit-dac",
+	0x02, "not-vga",
+	0x04, "ramdac-needs-blank",
+	0x08, "stereoscopic",
+	0x10, "stereo-evc",
+	0
+};
+
+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",
+	0
+};
+
+static Flag winattributesflags[] = {
+	1<<0, "relocatable",
+	1<<1, "readable",
+	1<<2, "writeable",
+	0
+};
+
+static Flag directcolorflags[] = {
+	1<<0, "programmable-color-ramp",
+	1<<1, "x-usable",
+	0
+};
+
+static char *modelstr[] = {
+	"text", "cga", "hercules", "planar", "packed", "non-chain4", "direct", "YUV"
+};
+
+static void
+printflags(Flag *f, int b)
+{
+	int i;
+
+	for(i=0; f[i].bit; i++)
+		if(f[i].bit & b)
+			Bprint(&stdout, " %s", f[i].desc);
+	Bprint(&stdout, "\n");
+}
+
+Vbe*
+mkvbe(void)
+{
+	Vbe *vbe;
+
+	vbe = alloc(sizeof(Vbe));
+	if((vbe->rmfd = open("/dev/realmode", ORDWR)) < 0)
+		return nil;
+	if((vbe->memfd = open("/dev/realmodemem", ORDWR)) < 0)
+		return nil;
+	vbe->mem = alloc(MemSize);
+	vbe->isvalid = alloc(MemSize/PageSize);
+	vbe->buf = alloc(PageSize);
+	vbe->modebuf = alloc(PageSize);
+	return vbe;
+}
+
+static void
+loadpage(Vbe *vbe, int p)
+{
+	if(p >= MemSize/PageSize || vbe->isvalid[p])
+		return;
+	if(pread(vbe->memfd, vbe->mem+p*PageSize, PageSize, p*PageSize) != PageSize)
+		error("read /dev/realmodemem: %r\n");
+	vbe->isvalid[p] = 1;
+}
+
+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;
+}
+
+uchar*
+vbesetup(Vbe *vbe, Ureg *u, int ax)
+{
+	memset(vbe->buf, 0, PageSize);
+	memset(u, 0, sizeof *u);
+	u->ax = ax;
+	u->es = (RealModeBuf>>4)&0xF000;
+	u->di = RealModeBuf&0xFFFF;
+	return vbe->buf;
+}
+
+int
+vbecall(Vbe *vbe, Ureg *u)
+{
+	u->trap = 0x10;
+	if(pwrite(vbe->memfd, vbe->buf, PageSize, RealModeBuf) != PageSize)
+		error("write /dev/realmodemem: %r\n");
+	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");
+	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)
+{
+	uchar *p;
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F00);
+	strcpy((char*)p, "VBE2");
+	if(vbecall(vbe, &u) < 0)
+		return -1;
+	if(memcmp(p, "VESA", 4) != 0 || p[5] < 2){
+		werrstr("invalid vesa signature %.4H %.4H\n", p, p+4);
+		return -1;
+	}
+	return 0;
+}
+
+int
+vbesnarf(Vbe *vbe, Vga *vga)
+{
+	uchar *p;
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F00);
+	strcpy((char*)p, "VBE2");
+	if(vbecall(vbe, &u) < 0)
+		return -1;
+	if(memcmp(p, "VESA", 4) != 0 || p[5] < 2)
+		return -1;
+	vga->apz = WORD(p+18)*0x10000UL;
+	return 0;
+}
+
+void
+vbeprintinfo(Vbe *vbe)
+{
+	uchar *p;
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F00);
+	strcpy((char*)p, "VBE2");
+	if(vbecall(vbe, &u) < 0)
+		return;
+
+	printitem("vesa", "sig");
+	Bprint(&stdout, "%.4s %d.%d\n", (char*)p, p[5], p[4]);
+	if(p[5] < 2)
+		return;
+
+	printitem("vesa", "oem");
+	Bprint(&stdout, "%s %d.%d\n", unfarptr(vbe, p+6), p[21], p[20]);
+	printitem("vesa", "vendor");
+	Bprint(&stdout, "%s\n", unfarptr(vbe, p+22));
+	printitem("vesa", "product");
+	Bprint(&stdout, "%s\n", unfarptr(vbe, p+26));
+	printitem("vesa", "rev");
+	Bprint(&stdout, "%s\n", unfarptr(vbe, p+30));
+
+	printitem("vesa", "cap");
+	printflags(capabilityflag, p[10]);
+
+	printitem("vesa", "mem");
+	Bprint(&stdout, "%lud\n", WORD(p+18)*0x10000UL);
+}
+
+uchar*
+vbemodes(Vbe *vbe)
+{
+	uchar *p;
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F00);
+	strcpy((char*)p, "VBE2");
+	if(vbecall(vbe, &u) < 0)
+		return nil;
+	memmove(vbe->modebuf, unfarptr(vbe, p+14), 1024);
+	return vbe->modebuf;
+}
+
+int
+vbemodeinfo(Vbe *vbe, int id, Vmode *m)
+{
+	int o;
+	ulong d, c, x;
+	uchar *p;
+	char tmp[sizeof m->chan];
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F01);
+	u.cx = id;
+	if(vbecall(vbe, &u) < 0)
+		return -1;
+
+	m->id = id;
+	m->attr = WORD(p);
+	m->bpl = WORD(p+16);
+	m->dx = WORD(p+18);
+	m->dy = WORD(p+20);
+	m->depth = p[25];
+	m->model = p[27] < nelem(modelstr) ? modelstr[p[27]] : "unknown";
+	m->r = p[31];
+	m->g = p[33];
+	m->b = p[35];
+	m->x = p[37];
+	m->ro = p[32];
+	m->go = p[34];
+	m->bo = p[36];
+	m->xo = p[38];
+	m->directcolor = p[39];
+	m->paddr = LONG(p+40);
+	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);
+		return 0;
+	}
+
+	m->xo = m->x = 0;
+	d = 1 << (m->depth - 1);
+	d |= d - 1;
+	c  = ((1<<m->r)-1) << m->ro;
+	c |= ((1<<m->g)-1) << m->go;
+	c |= ((1<<m->b)-1) << m->bo;
+	x = d ^ c;
+	if(x != 0){
+		for(; (x & 1) == 0; x >>= 1)
+			m->xo++;
+		for(; x & 1; x >>= 1)
+			m->x++;
+	}
+
+	m->chan[0] = o = 0;
+	while(o < m->depth){
+		if(m->r && m->ro == o){
+			snprint(tmp, sizeof tmp, "r%d%s", m->r, m->chan);
+			o += m->r;
+		}else if(m->g && m->go == o){
+			snprint(tmp, sizeof tmp, "g%d%s", m->g, m->chan);
+			o += m->g;
+		}else if(m->b && m->bo == o){
+			snprint(tmp, sizeof tmp, "b%d%s", m->b, m->chan);
+			o += m->b;
+		}else if(m->x && m->xo == o){
+			snprint(tmp, sizeof tmp, "x%d%s", m->x, m->chan);
+			o += m->x;
+		}else
+			break;
+		strncpy(m->chan, tmp, sizeof m->chan);
+	}
+	return 0;
+}
+
+void
+vbeprintmodeinfo(Vbe *vbe, int id, char *suffix)
+{
+	Vmode m;
+
+	if(vbemodeinfo(vbe, id, &m) < 0){
+	//	Bprint(&stdout, "vesa: cannot get mode 0x%ux: %r\n", id);
+		return;
+	}
+	printitem("vesa", "mode");
+	Bprint(&stdout, "0x%ux %s %s %s%s\n",
+		m.id, m.name, m.chan, m.model, suffix);
+}
+
+int
+vbegetmode(Vbe *vbe)
+{
+	Ureg u;
+
+	vbesetup(vbe, &u, 0x4F03);
+	if(vbecall(vbe, &u) < 0)
+		return 0;
+	return u.bx;
+}
+
+int
+vbesetmode(Vbe *vbe, int id)
+{
+	uchar *p;
+	Ureg u;
+
+	p = vbesetup(vbe, &u, 0x4F02);
+	if(id != 3)
+		id |= 3<<14;	/* graphics: use linear, do not clear */
+	u.bx = id;
+	USED(p);
+	/*
+	 * can set mode specifics (ht hss hse vt vss vse 0 clockhz refreshhz):
+	 *
+		u.bx |= 1<<11;
+		n = atoi(argv[2]); PWORD(p, n); p+=2;
+		n = atoi(argv[3]); PWORD(p, n); p+=2;
+		n = atoi(argv[4]); PWORD(p, n); p+=2;
+		n = atoi(argv[5]); PWORD(p, n); p+=2;
+		n = atoi(argv[6]); PWORD(p, n); p+=2;
+		n = atoi(argv[7]); PWORD(p, n); p+=2;
+		*p++ = atoi(argv[8]);
+		n = atoi(argv[9]); PLONG(p, n); p += 4;
+		n = atoi(argv[10]); PWORD(p, n); p += 2;
+		if(p != vbe.buf+19){
+			fprint(2, "prog error\n");
+			return;
+		}
+	 *
+	 */
+	return vbecall(vbe, &u);
+}
+
+void
+vesatextmode(void)
+{
+	if(vbe == nil){
+		vbe = mkvbe();
+		if(!vbe)
+			error("mkvbe: %r\n");
+	}
+	if(vbecheck(vbe) < 0)
+		error("vbecheck: %r\n");
+	if(vbesetmode(vbe, 3) < 0)
+		error("vbesetmode: %r\n");
+}
+
+static Flag edidflags[] = {
+	Fdigital, "digital",
+	Fdpmsstandby, "standby",
+	Fdpmssuspend, "suspend",
+	Fdpmsactiveoff, "activeoff",
+	Fmonochrome, "monochrome",
+	Fgtf, "gtf",
+	0
+};
+
+int parseedid128(Edid *e, void *v);
+
+int
+vbeddcedid(Vbe *vbe, Edid *e)
+{
+	uchar *p;
+	Ureg u;
+	
+	p = vbesetup(vbe, &u, 0x4F15);
+	u.bx = 0x0001;
+	if(vbecall(vbe, &u) < 0)
+		return -1;
+	if(parseedid128(e, p) < 0){
+		werrstr("parseedid128: %r");
+		return -1;
+	}
+	return 0;
+}
+	
+void
+printedid(Edid *e)
+{
+	Modelist *l;
+	
+	printitem("edid", "mfr");
+	Bprint(&stdout, "%s\n", e->mfr);
+	printitem("edid", "serialstr");
+	Bprint(&stdout, "%s\n", e->serialstr);
+	printitem("edid", "name");
+	Bprint(&stdout, "%s\n", e->name);
+	printitem("edid", "product");
+	Bprint(&stdout, "%d\n", e->product);
+	printitem("edid", "serial");
+	Bprint(&stdout, "%lud\n", e->serial);
+	printitem("edid", "version");
+	Bprint(&stdout, "%d.%d\n", e->version, e->revision);
+	printitem("edid", "mfrdate");
+	Bprint(&stdout, "%d.%d\n", e->mfryear, e->mfrweek);
+	printitem("edid", "size (cm)");
+	Bprint(&stdout, "%dx%d\n", e->dxcm, e->dycm);
+	printitem("edid", "gamma");
+	Bprint(&stdout, "%.2f\n", e->gamma/100.);
+	printitem("edid", "vert (Hz)");
+	Bprint(&stdout, "%d-%d\n", e->rrmin, e->rrmax);
+	printitem("edid", "horz (Hz)");
+	Bprint(&stdout, "%d-%d\n", e->hrmin, e->hrmax);
+	printitem("edid", "pclkmax");
+	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",
+			l->frequency/1.e6, l->shb, l->ehb, l->ht, l->vrs, l->vre, l->vt, l->hsync?l->hsync:'?', l->vsync?l->vsync:'?', l->interlace?"interlace=v" : "");
+	}
+}
+
+Modelist*
+addmode(Modelist *l, Mode m)
+{
+	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);
+
+	if(m.shs == 0)
+		m.shs = m.shb;
+	if(m.ehs == 0)
+		m.ehs = m.ehb;
+	if(m.vbs == 0)
+		m.vbs = m.vrs;
+	if(m.vbe == 0)
+		m.vbe = m.vbs+1;
+
+	for(lp=&l; *lp; lp=&(*lp)->next){
+		if(strcmp((*lp)->name, m.name) == 0){
+			(*lp)->Mode = m;
+			return l;
+		}
+	}
+
+	*lp = alloc(sizeof(**lp));
+	(*lp)->Mode = m;
+	return l;
+}
+
+/*
+ * Parse VESA EDID information.  Based on the VESA
+ * Extended Display Identification Data standard, Version 3,
+ * November 13, 1997.  See /public/doc/vesa/edidv3.pdf.
+ *
+ * This only handles 128-byte EDID blocks.  Until I find
+ * a monitor that produces 256-byte blocks, I'm not going
+ * to try to decode them.
+ */
+
+/*
+ * Established timings block.  There is a bitmap
+ * that says whether each mode is supported.  Most
+ * of these have VESA definitions.  Those that don't are marked
+ * as such, and we ignore them (the lookup fails).
+ */
+static char *estabtime[] = {
+	"720x400@70Hz",	/* non-VESA: IBM, VGA */
+	"720x400@88Hz",	/* non-VESA: IBM, XGA2 */
+	"640x480@60Hz",
+	"640x480@67Hz",	/* non-VESA: Apple, Mac II */
+	"640x480@72Hz",
+	"640x480@75Hz",
+	"800x600@56Hz",
+	"800x600@60Hz",
+
+	"800x600@72Hz",
+	"800x600@75Hz",
+	"832x624@75Hz",	/* non-VESA: Apple, Mac II */
+	"1024x768i@87Hz",	/* non-VESA: IBM */
+	"1024x768@60Hz",
+	"1024x768@70Hz",
+	"1024x768@75Hz",
+	"1280x1024@75Hz",
+
+	"1152x870@75Hz",	/* non-VESA: Apple, Mac II */
+};
+
+/*
+ * Decode the EDID detailed timing block.  See pp. 20-21 of the standard.
+ */
+static int
+decodedtb(Mode *m, uchar *p)
+{
+	int ha, hb, hso, hspw, rr, va, vb, vso, vspw;
+	/* int dxmm, dymm, hbord, vbord; */
+
+	memset(m, 0, sizeof *m);
+
+	m->frequency = ((p[1]<<8) | p[0]) * 10000;
+
+	ha = ((p[4] & 0xF0)<<4) | p[2];		/* horizontal active */
+	hb = ((p[4] & 0x0F)<<8) | p[3];		/* horizontal blanking */
+	va = ((p[7] & 0xF0)<<4) | p[5];		/* vertical active */
+	vb = ((p[7] & 0x0F)<<8) | p[6];		/* vertical blanking */
+	hso = ((p[11] & 0xC0)<<2) | p[8];	/* horizontal sync offset */
+	hspw = ((p[11] & 0x30)<<4) | p[9];	/* horizontal sync pulse width */
+	vso = ((p[11] & 0x0C)<<2) | ((p[10] & 0xF0)>>4);	/* vertical sync offset */
+	vspw = ((p[11] & 0x03)<<4) | (p[10] & 0x0F);		/* vertical sync pulse width */
+
+	/* dxmm = (p[14] & 0xF0)<<4) | p[12]; 	/* horizontal image size (mm) */
+	/* dymm = (p[14] & 0x0F)<<8) | p[13];	/* vertical image size (mm) */
+	/* hbord = p[15];		/* horizontal border (pixels) */
+	/* vbord = p[16];		/* vertical border (pixels) */
+
+	m->x = ha;
+	m->y = va;
+
+	m->ht = ha+hb;
+	m->shs = ha;
+	m->shb = ha+hso;
+	m->ehb = ha+hso+hspw;
+	m->ehs = ha+hb;
+
+	m->vt = va+vb;
+	m->vbs = va;	
+	m->vrs = va+vso;
+	m->vre = va+vso+vspw;
+	m->vbe = va+vb;
+
+	if(p[17] & 0x80)	/* interlaced */
+		m->interlace = 'v';
+
+	if(p[17] & 0x60)	/* some form of stereo monitor mode; no support */
+		return -1;
+
+	/*
+	 * Sync signal description.  I have no idea how to properly handle the 
+	 * first three cases, which I think are aimed at things other than
+	 * canonical SVGA monitors.
+	 */
+	switch((p[17] & 0x18)>>3) {
+	case 0:	/* analog composite sync signal*/
+	case 1:	/* bipolar analog composite sync signal */
+		/* p[17] & 0x04 means serration: hsync during vsync */
+		/* p[17] & 0x02 means sync pulse appears on RGB not just G */
+		break;
+
+	case 2:	/* digital composite sync signal */
+		/* p[17] & 0x04 means serration: hsync during vsync */
+		/* p[17] & 0x02 means hsync positive outside vsync */
+		break;
+
+	case 3:	/* digital separate sync signal; the norm */
+		m->vsync = (p[17] & 0x04) ? '+' : '-';
+		m->hsync = (p[17] & 0x02) ? '+' : '-';
+		break;
+	}
+	/* p[17] & 0x01 is another stereo bit, only referenced if p[17] & 0x60 != 0 */
+
+	rr = (m->frequency+m->ht*m->vt/2) / (m->ht*m->vt);
+
+	snprint(m->name, sizeof m->name, "%dx%d@%dHz", m->x, m->y, rr);
+
+	return 0;
+}
+
+extern Mode *vesamodes[];
+
+int
+vesalookup(Mode *m, char *name)
+{
+	Mode **p;
+
+	for(p=vesamodes; *p; p++)
+		if(strcmp((*p)->name, name) == 0) {
+			*m = **p;
+			return 0;
+		}
+
+	return -1;
+}
+
+static int
+decodesti(Mode *m, uchar *p)
+{
+	int x, y, rr;
+	char str[20];
+
+	x = (p[0]+31)*8;
+	switch((p[1]>>6) & 3){
+	default:
+	case 0:
+		y = x;
+		break;
+	case 1:
+		y = (x*4)/3;
+		break;
+	case 2:
+		y = (x*5)/4;
+		break;
+	case 3:
+		y = (x*16)/9;
+		break;
+	}
+	rr = (p[1] & 0x1F) + 60;
+
+	sprint(str, "%dx%d@%dHz", x, y, rr);
+	return vesalookup(m, str);
+}
+
+int
+parseedid128(Edid *e, void *v)
+{
+	static uchar magic[8] = { 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00 };
+	uchar *p, *q, sum;
+	int dpms, estab, i, m, vid;
+	Mode mode;
+
+	memset(e, 0, sizeof *e);
+
+	p = (uchar*)v;
+	if(memcmp(p, magic, 8) != 0) {
+		werrstr("bad edid header");
+		return -1;
+	}
+
+	sum = 0;
+	for(i=0; i<128; i++) 
+		sum += p[i];
+	if(sum != 0) {
+		werrstr("bad edid checksum");
+		return -1;
+	}
+	p += 8;
+
+	assert(p == (uchar*)v+8);	/* assertion offsets from pp. 12-13 of the standard */
+	/*
+	 * Manufacturer name is three 5-bit ascii letters, packed
+	 * into a big endian [sic] short in big endian order.  The high bit is unused.
+	 */
+	i = (p[0]<<8) | p[1];
+	p += 2;
+	e->mfr[0] = 'A'-1 + ((i>>10) & 0x1F);
+	e->mfr[1] = 'A'-1 + ((i>>5) & 0x1F);
+	e->mfr[2] = 'A'-1 + (i & 0x1F);
+	e->mfr[3] = '\0';
+
+	/*
+	 * Product code is a little endian short.
+	 */
+	e->product = (p[1]<<8) | p[0];
+	p += 2;
+
+	/*
+	 * Serial number is a little endian long, 0x01010101 = unused.
+	 */
+	e->serial = (p[3]<<24) | (p[2]<<16) | (p[1]<<8) | p[0];
+	p += 4;
+	if(e->serial == 0x01010101)
+		e->serial = 0;
+
+	e->mfrweek = *p++;
+	e->mfryear = 1990 + *p++;
+
+	assert(p == (uchar*)v+8+10);
+	/*
+	 * Structure version is next two bytes: major.minor.
+	 */
+	e->version = *p++;
+	e->revision = *p++;
+
+	assert(p == (uchar*)v+8+10+2);
+	/*
+	 * Basic display parameters / features.
+	 */
+	/*
+	 * Video input definition byte: 0x80 tells whether it is
+	 * an analog or digital screen; we ignore the other bits.
+	 * See p. 15 of the standard.
+	 */
+	vid = *p++;
+	if(vid & 0x80)
+		e->flags |= Fdigital;
+
+	e->dxcm = *p++;
+	e->dycm = *p++;
+	e->gamma = 100 + *p++;
+	dpms = *p++;
+	if(dpms & 0x80)
+		e->flags |= Fdpmsstandby;
+	if(dpms & 0x40)
+		e->flags |= Fdpmssuspend;
+	if(dpms & 0x20)
+		e->flags |= Fdpmsactiveoff;
+	if((dpms & 0x18) == 0x00)
+		e->flags |= Fmonochrome;
+	if(dpms & 0x01)
+		e->flags |= Fgtf;
+
+	assert(p == (uchar*)v+8+10+2+5);
+	/*
+	 * Color characteristics currently ignored.
+	 */
+	p += 10;
+
+	assert(p == (uchar*)v+8+10+2+5+10);
+	/*
+	 * Established timings: a bitmask of 19 preset timings.
+	 */
+	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)
+				e->modelist = addmode(e->modelist,  mode);
+
+	assert(p == (uchar*)v+8+10+2+5+10+3);
+	/*
+	 * Standard Timing Identifications: eight 2-byte selectors
+	 * of more standard timings.
+	 */
+	for(i=0; i<8; i++, p+=2)
+		if(decodesti(&mode, p+2*i) == 0)
+			e->modelist = addmode(e->modelist, mode);
+
+	assert(p == (uchar*)v+8+10+2+5+10+3+16);
+	/*
+	 * 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);
+		} else if(p[2]==0) {	/* monitor descriptor block */
+			switch(p[3]) {
+			case 0xFF:	/* monitor serial number (13-byte ascii, 0A terminated) */
+				if(q = memchr(p+5, 0x0A, 13))
+					*q = '\0';
+				memset(e->serialstr, 0, sizeof(e->serialstr));
+				strncpy(e->serialstr, (char*)p+5, 13);
+				break;
+			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;
+				e->hrmax = p[8]*1000;
+				if(p[9] != 0xFF)
+					e->pclkmax = p[9]*10*1000000;
+				break;
+			case 0xFC:	/* monitor name (13-byte ascii, 0A terminated) */
+				if(q = memchr(p+5, 0x0A, 13))
+					*q = '\0';
+				memset(e->name, 0, sizeof(e->name));
+				strncpy(e->name, (char*)p+5, 13);
+				break;
+			case 0xFB:	/* extra color point data */
+				break;
+			case 0xFA:	/* extra standard timing identifications */
+				for(i=0; i<6; i++)
+					if(decodesti(&mode, p+5+2*i) == 0)
+						e->modelist = addmode(e->modelist, mode);
+				break;
+			}
+		}
+	}
+
+	assert(p == (uchar*)v+8+10+2+5+10+3+16+72);
+	return 0;
+}