Make the usb/kb debug flag local to each device instead of global,
to make it easier to debug multiple devices, and prevent inadvertent
promotion of -d to -dd when extra devices are started.
Also fallback to boot protocol if fetching the report descriptor returns
zero bytes (should be impossible but it's been observed).

Reference: /n/sources/patch/applied/usb-kb-debug
Date: Tue Dec 18 20:52:44 CET 2012
Signed-off-by: miller@hamnavoe.com

--- /sys/src/cmd/usb/kb/kb.c	Thu Dec 13 21:34:14 2012
+++ /sys/src/cmd/usb/kb/kb.c	Tue Dec 18 20:51:13 2012
@@ -36,6 +36,7 @@
 	Channel*repeatc;	/* only for keyboard */
 	int	accel;		/* only for mouse */
 	int	bootp;		/* has associated keyboard */
+	int	debug;
 	HidRepTempl templ;
 	int	(*ptrvals)(KDev *kd, Chain *ch, int *px, int *py, int *pb);
 };
@@ -118,8 +119,6 @@
 	.fd = -1,
 };
 
-static int kbdebug;
-
 static int ptrbootpvals(KDev *kd, Chain *ch, int *px, int *py, int *pb);
 static int ptrrepvals(KDev *kd, Chain *ch, int *px, int *py, int *pb);
 
@@ -153,7 +152,7 @@
 	}
 	id = f->dev->usb->ep[eid]->iface->id;
 	r = Rh2d | Rstd | Rdev;
-	nr =usbcmd(f->dev,  r, Rsetconf, 1, id, nil, 0);
+	nr = usbcmd(f->dev,  r, Rsetconf, 1, 0, nil, 0);
 	if(nr < 0)
 		return -1;
 	r = Rh2d | Rclass | Riface;
@@ -162,9 +161,9 @@
 		return -1;
 	r = Rd2h | Rstd | Riface;
 	nr=usbcmd(f->dev,  r, Rgetdesc, Dreport<<8, id, desc, descsz);
-	if(nr < 0)
+	if(nr <= 0)
 		return -1;
-	if(kbdebug && nr > 0){
+	if(f->debug){
 		fprint(2, "report descriptor:");
 		for(i = 0; i < nr; i++){
 			if(i%8 == 0)
@@ -290,7 +289,7 @@
 			return -1;
 	parsereport(&kd->templ, ch);
 
-	if(kbdebug)
+	if(kd->debug > 1)
 		dumpreport(&kd->templ);
 	if(c < 3)
 		return -1;
@@ -378,7 +377,7 @@
 			x = scale(f, x);
 			y = scale(f, y);
 		}
-		if(kbdebug > 1)
+		if(f->debug > 1)
 			fprint(2, "kb: m%11d %11d %11d\n", x, y, b);
 		seprint(mbuf, mbuf+sizeof(mbuf), "m%11d %11d %11d", x, y,b);
 		if(write(mfd, mbuf, strlen(mbuf)) < 0)
@@ -409,19 +408,21 @@
 }
 
 static void
-putscan(int kbinfd, uchar esc, uchar sc)
+putscan(KDev *f, uchar esc, uchar sc)
 {
+	int kbinfd;
 	uchar s[2] = {SCesc1, 0};
 
+	kbinfd = f->in->fd;
 	if(sc == 0x41){
-		kbdebug += 2;
+		f->debug += 2;
 		return;
 	}
 	if(sc == 0x42){
-		kbdebug = 0;
+		f->debug = 0;
 		return;
 	}
-	if(kbdebug)
+	if(f->debug > 1)
 		fprint(2, "sc: %x %x\n", (esc? SCesc1: 0), sc);
 	s[1] = sc;
 	if(esc && sc != 0)
@@ -435,7 +436,6 @@
 {
 	KDev *f;
 	Channel *repeatc;
-	int kbdinfd;
 	ulong l, t, i;
 	uchar esc1, sc;
 
@@ -446,7 +446,6 @@
 	 */
 	f = a;
 	repeatc = f->repeatc;
-	kbdinfd = f->in->fd;
 	l = Awakemsg;
 Repeat:
 	if(l == Diemsg)
@@ -464,7 +463,7 @@
 				goto Repeat;
 			sleep(5);
 		}
-		putscan(kbdinfd, esc1, sc);
+		putscan(f, esc1, sc);
 		t = 30;
 	}
 Abort:
@@ -477,13 +476,13 @@
 #define hasesc1(sc)	(((sc) > 0x47) || ((sc) == 0x38))
 
 static void
-putmod(int fd, uchar mods, uchar omods, uchar mask, uchar esc, uchar sc)
+putmod(KDev *f, uchar mods, uchar omods, uchar mask, uchar esc, uchar sc)
 {
 	/* BUG: Should be a single write */
 	if((mods&mask) && !(omods&mask))
-		putscan(fd, esc, sc);
+		putscan(f, esc, sc);
 	if(!(mods&mask) && (omods&mask))
-		putscan(fd, esc, Keyup|sc);
+		putscan(f, esc, Keyup|sc);
 }
 
 /*
@@ -499,14 +498,12 @@
 {
 	int i, j;
 	uchar uk;
-	int fd;
 
-	fd = f->in->fd;
-	putmod(fd, buf[0], obuf[0], Mctrl, 0, SCctrl);
-	putmod(fd, buf[0], obuf[0], (1<<Mlshift), 0, SClshift);
-	putmod(fd, buf[0], obuf[0], (1<<Mrshift), 0, SCrshift);
-	putmod(fd, buf[0], obuf[0], Mcompose, 0, SCcompose);
-	putmod(fd, buf[0], obuf[0], Maltgr, 1, SCcompose);
+	putmod(f, buf[0], obuf[0], Mctrl, 0, SCctrl);
+	putmod(f, buf[0], obuf[0], (1<<Mlshift), 0, SClshift);
+	putmod(f, buf[0], obuf[0], (1<<Mrshift), 0, SCrshift);
+	putmod(f, buf[0], obuf[0], Mcompose, 0, SCcompose);
+	putmod(f, buf[0], obuf[0], Maltgr, 1, SCcompose);
 
 	/* Report key downs */
 	for(i = 2; i < n; i++){
@@ -515,7 +512,7 @@
 			 	break;
 		if(j == n && buf[i] != 0){
 			dk = sctab[buf[i]];
-			putscan(fd, hasesc1(dk), dk);
+			putscan(f, hasesc1(dk), dk);
 			startrepeat(f, hasesc1(dk), dk);
 		}
 	}
@@ -528,7 +525,7 @@
 				break;
 		if(j == n && obuf[i] != 0){
 			uk = sctab[obuf[i]];
-			putscan(fd, hasesc1(uk), uk|Keyup);
+			putscan(f, hasesc1(uk), uk|Keyup);
 		}
 	}
 	if(uk && (dk == 0 || dk == uk)){
@@ -589,7 +586,7 @@
 			continue;
 		if(kbdbusy(buf + 2, c - 2))
 			continue;
-		if(usbdebug > 2 || kbdebug > 1){
+		if(usbdebug > 2 || f->debug > 1){
 			fprint(2, "kbd mod %x: ", buf[0]);
 			for(i = 2; i < c; i++)
 				fprint(2, "kc %x ", buf[i]);
@@ -669,7 +666,7 @@
 			fprint(2, "kb: %s: bootproto: %r\n", d->dir);
 			return;
 		}
-	}else if(kbdebug)
+	}else if(kd->debug)
 		dumpreport(&kd->templ);
 	if(opendevdata(kd->ep, OREAD) < 0){
 		fprint(2, "kb: %s: opendevdata: %r\n", kd->ep->dir);
@@ -692,7 +689,7 @@
 int
 kbmain(Dev *d, int argc, char* argv[])
 {
-	int bootp, i, kena, pena, accel, devid;
+	int bootp, i, kena, pena, accel, devid, debug;
 	Ep *ep;
 	KDev *kd;
 	Usbdev *ud;
@@ -700,13 +697,14 @@
 	kena = pena = 1;
 	bootp = 0;
 	accel = 0;
+	debug = 0;
 	devid = d->id;
 	ARGBEGIN{
 	case 'a':
 		accel = strtol(EARGF(usage()), nil, 0);
 		break;
 	case 'd':
-		kbdebug++;
+		debug++;
 		break;
 	case 'k':
 		kena = 1;
@@ -747,6 +745,7 @@
 			kd = d->aux = emallocz(sizeof(KDev), 1);
 			kd->accel = 0;
 			kd->bootp = 1;
+			kd->debug = debug;
 			kbstart(d, ep, &kbdin, kbdwork, kd);
 		}
 		if(pena && ep->type == Eintr && ep->dir == Ein &&
@@ -754,6 +753,7 @@
 			kd = d->aux = emallocz(sizeof(KDev), 1);
 			kd->accel = accel;
 			kd->bootp = bootp;
+			kd->debug = debug;
 			kbstart(d, ep, &ptrin, ptrwork, kd);
 		}
 	}