nusb/usbd: use per hname collision counter instead of device address to resolve collisions

The device address is highly variable and depends on
all prior enumerated devices.

This can happen with some devices that do not have
a serial number and all devices of the same type
having the same hname.

Using a counter of collisions per hname makes more sense
and is more stable (given that the order devices are
enumerated is deterministic).

3 files changed, 14 insertions, 10 deletions

diff --git a/sys/src/cmd/nusb/usbd/fns.h b/sys/src/cmd/nusb/usbd/fns.h
index 2368b8296..4bd584188 100644
--- a/sys/src/cmd/nusb/usbd/fns.h
+++ b/sys/src/cmd/nusb/usbd/fns.h
@@ -2,5 +2,5 @@ int	attachdev(Port*);
 void	detachdev(Port*);
 void	work(void);
 Hub*	newhub(char *, Dev*);
-void	hname(char *);
+int	hname(char *);
 void	checkidle(void);
diff --git a/sys/src/cmd/nusb/usbd/hname.c b/sys/src/cmd/nusb/usbd/hname.c
index c88a0faa1..deeb6685c 100644
--- a/sys/src/cmd/nusb/usbd/hname.c
+++ b/sys/src/cmd/nusb/usbd/hname.c
@@ -3,7 +3,7 @@
 #include <mp.h>
 #include <libsec.h>
 
-void
+int
 hname(char *buf)
 {
 	uchar d[SHA1dlen];
@@ -13,5 +13,5 @@ hname(char *buf)
 	n = strlen(buf);
 	sha1((uchar*)buf, n, d, nil);
 	x = d[0] | d[1]<<8 | d[2]<<16;
-	snprint(buf, n+1, "%.5ux", x & 0xfffff);
+	return snprint(buf, n+1, "%.5ux", x & 0xfffff);
 }
diff --git a/sys/src/cmd/nusb/usbd/usbd.c b/sys/src/cmd/nusb/usbd/usbd.c
index 4c2d70100..42930c5b8 100644
--- a/sys/src/cmd/nusb/usbd/usbd.c
+++ b/sys/src/cmd/nusb/usbd/usbd.c
@@ -363,7 +363,8 @@ assignhname(Dev *dev)
 	char buf[64];
 	Usbdev *ud;
 	Hub *h;
-	int i;
+	int col;
+	int i, n;
 
 	ud = dev->usb;
 
@@ -371,22 +372,25 @@ assignhname(Dev *dev)
 	snprint(buf, sizeof(buf), "%.4x%.4x%.4x%.6lx%s",
 		ud->vid, ud->did, ud->dno, ud->csp, ud->serial);
 
-	hname(buf);
+	n = hname(buf);
 
 	/* check for collisions */
+	col = 0;
 	for(h = hubs; h != nil; h = h->next){
 		for(i = 1; i <= h->nport; i++){
 			if(h->port[i].dev == nil)
 				continue;
 			if(h->port[i].dev->hname == nil || h->port[i].dev == dev)
 				continue;
-			if(strcmp(h->port[i].dev->hname, buf) == 0){
-				dev->hname = smprint("%s%d", buf, dev->id);
-				return;
-			}
+			if(strncmp(h->port[i].dev->hname, buf, n) == 0)
+				col++;
 		}
 	}
-	dev->hname = strdup(buf);
+
+	if(col == 0)
+		dev->hname = strdup(buf);
+	else
+		dev->hname = smprint("%s%d", buf, col);
 }
 
 int