keep descriptor sizes to a minimum
disambiguate error messages
use pread not seek+read
eliminate unused and misleading setting of bMaxPacketSize0
before a call to read on top of that data.

Reference: /n/atom/patch/applied/usbdsmalldesc
Date: Tue Apr  1 04:17:13 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/usb/usbd/usbd.c	Tue Apr  1 04:15:47 2014
+++ /sys/src/cmd/usb/usbd/usbd.c	Tue Apr  1 04:15:49 2014
@@ -53,14 +53,14 @@
 confighub(Hub *h)
 {
 	int type;
-	uchar buf[128];	/* room for extra descriptors */
+	uchar buf[64];	/* room for extra descriptors */
 	int i;
 	Usbdev *d;
 	DHub *dd;
 	Port *pp;
 	int nr;
 	int nmap;
-	uchar *PortPwrCtrlMask;
+	uchar *pwrctlmask;
 	int offset;
 	int mask;
 
@@ -93,15 +93,15 @@
 		h->pwrms = Powerdelay;
 	h->maxcurrent = dd->bHubContrCurrent;
 	h->pwrmode = dd->wHubCharacteristics[0] & 3;
-	h->compound = (dd->wHubCharacteristics[0] & (1<<2))!=0;
+	h->compound = (dd->wHubCharacteristics[0] & (1<<2)) != 0;
 	h->leds = (dd->wHubCharacteristics[0] & (1<<7)) != 0;
-	PortPwrCtrlMask = dd->DeviceRemovable + nmap;
+	pwrctlmask = dd->DeviceRemovable + nmap;
 	for(i = 1; i <= h->nport; i++){
 		pp = &h->port[i];
 		offset = i/8;
 		mask = 1<<(i%8);
 		pp->removable = (dd->DeviceRemovable[offset] & mask) != 0;
-		pp->pwrctl = (PortPwrCtrlMask[offset] & mask) != 0;
+		pp->pwrctl = (pwrctlmask[offset] & mask) != 0;
 	}
 	return 0;
 }
@@ -117,8 +117,7 @@
 	d = h->dev;
 	h->nport = 2;
 	h->maxpkt = 8;
-	seek(d->cfd, 0, 0);
-	nr = read(d->cfd, buf, sizeof(buf)-1);
+	nr = pread(d->cfd, buf, sizeof(buf)-1, 0);
 	if(nr < 0)
 		goto Done;
 	buf[nr] = 0;
@@ -296,16 +295,12 @@
 }
 
 static int
-getmaxpkt(Dev *d, int islow)
+getmaxpkt(Dev *d)
 {
-	uchar buf[64];	/* More room to try to get device-specific descriptors */
+	uchar buf[Ddevlen];
 	DDev *dd;
 
 	dd = (DDev*)buf;
-	if(islow)
-		dd->bMaxPacketSize0 = 8;
-	else
-		dd->bMaxPacketSize0 = 64;
 	if(usbcmd(d, Rd2h|Rstd|Rdev, Rgetdesc, Ddev<<8|0, 0, buf, sizeof(buf)) < 0)
 		return -1;
 	return dd->bMaxPacketSize0;
@@ -361,8 +356,7 @@
 		fprint(2, "%s: %s: port %d: newdev: %r\n", argv0, d->dir, p);
 		goto Fail;
 	}
-	seek(d->cfd, 0, 0);
-	nr = read(d->cfd, buf, sizeof(buf)-1);
+	nr = pread(d->cfd, buf, sizeof(buf)-1, 0);
 	if(nr == 0){
 		fprint(2, "%s: %s: port %d: newdev: eof\n", argv0, d->dir, p);
 		goto Fail;
@@ -385,15 +379,15 @@
 		goto Fail;
 	}
 	if(usbcmd(nd, Rh2d|Rstd|Rdev, Rsetaddress, nd->id, 0, nil, 0) < 0){
-		dprint(2, "%s: %s: port %d: setaddress: %r\n", argv0, d->dir, p);
+		dprint(2, "%s: %s: port %d: attach setaddress: %r\n", argv0, d->dir, p);
 		goto Fail;
 	}
 	if(devctl(nd, "address") < 0){
-		dprint(2, "%s: %s: port %d: set address: %r\n", argv0, d->dir, p);
+		dprint(2, "%s: %s: port %d: attach set address: %r\n", argv0, d->dir, p);
 		goto Fail;
 	}
 
-	mp=getmaxpkt(nd, strcmp(sp, "low") == 0);
+	mp = getmaxpkt(nd);
 	if(mp < 0){
 		dprint(2, "%s: %s: port %d: getmaxpkt: %r\n", argv0, d->dir, p);
 		goto Fail;
@@ -530,11 +524,11 @@
 	nd = pp->dev;
 	opendevdata(nd, ORDWR);
 	if(usbcmd(nd, Rh2d|Rstd|Rdev, Rsetaddress, nd->id, 0, nil, 0) < 0){
-		dprint(2, "%s: %s: port %d: setaddress: %r\n", argv0, d->dir, p);
+		dprint(2, "%s: %s: rst port %d: setaddress: %r\n", argv0, d->dir, p);
 		goto Fail;
 	}
 	if(devctl(nd, "address") < 0){
-		dprint(2, "%s: %s: port %d: set address: %r\n", argv0, d->dir, p);
+		dprint(2, "%s: %s: rst port %d: set address: %r\n", argv0, d->dir, p);
 		goto Fail;
 	}
 	if(usbcmd(nd, Rh2d|Rstd|Rdev, Rsetconf, 1, 0, nil, 0) < 0){
@@ -873,6 +867,7 @@
 	args();
 
 	fmtinstall('U', Ufmt);
+	fmtinstall('H', encodefmt);
 	quotefmtinstall();
 	rfork(RFNOTEG);
 	portc = chancreate(sizeof(char *), 0);
--- /sys/src/cmd/usb/usbd/usbd.h	Tue Apr  1 04:15:50 2014
+++ /sys/src/cmd/usb/usbd/usbd.h	Tue Apr  1 04:15:51 2014
@@ -52,9 +52,7 @@
 	Pconfiged,
 
 	/* Delays, timeouts (ms) */
-//	Spawndelay	= 1000,		/* how often may we re-spawn a driver */
 	Spawndelay	= 250,		/* how often may we re-spawn a driver */
-//	Connectdelay	= 1000,		/* how much to wait after a connect */
 	Connectdelay	= 500,		/* how much to wait after a connect */
 	Resetdelay	= 20,		/* how much to wait after a reset */
 	Enabledelay	= 20,		/* how much to wait after an enable */