this sidebar in the sd stuff should be retired by now, but it's not.
so make sure that it handles 64-bit lbas.

Reference: /n/atom/patch/applied/nixscsi64bitlba
Date: Thu Mar 27 05:43:22 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/port/devsd.c	Thu Mar 27 05:42:38 2014
+++ /sys/src/nix/port/devsd.c	Thu Mar 27 05:42:39 2014
@@ -524,7 +524,7 @@
 	case Qtopdir:
 		if(s == DEVDOTDOT){
 			mkqid(&q, QID(0, 0, 0, Qtopdir), 0, QTDIR);
-			sprint(up->genbuf, "#%C", sddevtab.dc);
+			snprint(up->genbuf, sizeof up->genbuf, "#%C", sddevtab.dc);
 			devdir(c, q, up->genbuf, 0, eve, 0555, dp);
 			return 1;
 		}
@@ -572,7 +572,7 @@
 	case Qunitdir:
 		if(s == DEVDOTDOT){
 			mkqid(&q, QID(0, 0, 0, Qtopdir), 0, QTDIR);
-			sprint(up->genbuf, "#%C", sddevtab.dc);
+			snprint(up->genbuf, sizeof up->genbuf, "#%C", sddevtab.dc);
 			devdir(c, q, up->genbuf, 0, eve, 0555, dp);
 			return 1;
 		}
--- /sys/src/nix/port/sdscsi.c	Thu Mar 27 05:42:41 2014
+++ /sys/src/nix/port/sdscsi.c	Thu Mar 27 05:42:42 2014
@@ -113,6 +113,74 @@
 	return 0;
 }
 
+static void
+cap10(SDreq *r)
+{
+	r->cmd[0] = 0x25;
+	r->cmd[1] = r->lun<<5;
+	r->clen = 10;
+	r->dlen = 8;
+}
+
+static void
+cap16(SDreq *r)
+{
+	uint i;
+
+	i = 32;
+	r->cmd[0] = 0x9e;
+	r->cmd[1] = 0x10;
+	r->cmd[10] = i>>24;
+	r->cmd[11] = i>>16;
+	r->cmd[12] = i>>8;
+	r->cmd[13] = i;
+	r->clen = 16;
+	r->dlen = i;
+}
+
+static uint
+belong(uchar *u)
+{
+	return u[0]<<24 | u[1]<<16 | u[2]<<8 | u[3];
+}
+
+static uvlong
+capreply(SDreq *r, ulong *secsize)
+{
+	uchar *u;
+	ulong ss;
+	uvlong s;
+
+	*secsize = 0;
+	u = r->data;
+	if(r->clen == 16){
+		s = (uvlong)belong(u)<<32 | belong(u + 4);
+		ss = belong(u + 8);
+	}else{
+		s = belong(u);
+		ss = belong(u + 4);
+	}
+	/*
+	 * Some ATAPI CD readers lie about the block size.
+	 * Since we don't read audio via this interface
+	 * it's okay to always fudge this.
+	 */
+	if(ss == 2352)
+		ss = 2048;
+	/*
+	 * Devices with removable media may return 0 sectors
+	 * when they have empty media (e.g. sata dvd writers);
+	 * if so, keep the count zero.
+	 *
+	 * Read-capacity returns the LBA of the last sector,
+	 * therefore the number of sectors must be incremented.
+	 */
+	if(s != 0)
+		s++;
+	*secsize = ss;
+	return s;
+}
+
 static int
 scsirio(SDreq* r)
 {
@@ -151,7 +219,8 @@
 			/*
 			 * If no medium present, bail out.
 			 * If unit is becoming ready, rather than not
-			 * not ready, wait a little then poke it again. 				 */
+			 * not ready, wait a little then poke it again.
+ 			 */
 			if(r->sense[12] == 0x3A)
 				break;
 			if(r->sense[12] != 0x04 || r->sense[13] != 0x01)
@@ -179,16 +248,17 @@
 	SDreq *r;
 	uchar *p;
 	int ok, retries;
+	void (*cap)(SDreq*);
 
-	if((r = malloc(sizeof(SDreq))) == nil)
+	if((r = malloc(sizeof *r)) == nil)
 		return 0;
-	if((p = sdmalloc(8)) == nil){
+	if((p = sdmalloc(32)) == nil){
 		free(r);
 		return 0;
 	}
 
 	ok = 0;
-
+	cap = cap10;
 	r->unit = unit;
 	r->lun = 0;				/* ??? */
 	for(retries = 0; retries < 10; retries++){
@@ -199,39 +269,21 @@
 		 * plain slow getting their act together after a reset.
 		 */
 		r->write = 0;
-		memset(r->cmd, 0, sizeof(r->cmd));
-		r->cmd[0] = 0x25;
-		r->cmd[1] = r->lun<<5;
-		r->clen = 10;
 		r->data = p;
-		r->dlen = 8;
 		r->flags = 0;
+		memset(r->cmd, 0, sizeof r->cmd);
+		cap(r);
 
 		r->status = ~0;
 		switch(scsirio(r)){
 		default:
 			break;
 		case 0:
-			unit->sectors = (p[0]<<24)|(p[1]<<16)|(p[2]<<8)|p[3];
-			unit->secsize = (p[4]<<24)|(p[5]<<16)|(p[6]<<8)|p[7];
-
-			/*
-			 * Some ATAPI CD readers lie about the block size.
-			 * Since we don't read audio via this interface
-			 * it's okay to always fudge this.
-			 */
-			if(unit->secsize == 2352)
-				unit->secsize = 2048;
-			/*
-			 * Devices with removable media may return 0 sectors
-			 * when they have empty media (e.g. sata dvd writers);
-			 * if so, keep the count zero.
-			 *
-			 * Read-capacity returns the LBA of the last sector,
-			 * therefore the number of sectors must be incremented.
-			 */
-			if(unit->sectors != 0)
-				unit->sectors++;
+			unit->sectors = capreply(r, &unit->secsize);
+			if(unit->sectors == 0xffffffff && cap == cap10){
+				cap = cap16;
+				continue;
+			}
 			ok = 1;
 			break;
 		case 1: