git: plan9front

Info  •  Files  •  Log  •  Branches

nusb/usbd: maintain hublist order with rootports first

This ensures that on a portstatus() error or port
detach, we always restart enumeration from the
rootports down and avoid talking to intermediate
hubs that are in the tree that got disconnected.

--- a/sys/src/cmd/nusb/usbd/hub.c

+++ b/sys/src/cmd/nusb/usbd/hub.c

@@ -187,7 +187,7 @@

 Hub*

 newhub(char *fn, Dev *d)

 {

-	Hub *h;

+	Hub *h, **hl;

 	int i;

 	Usbdev *ud;

@@ -232,8 +232,11 @@

 		for(i = 1; i <= h->nport; i++)

 			portfeature(h, i, Fportindicator, 1);

 	}

-	h->next = hubs;

-	hubs = h;

+	/* link to tail, so we always enumarte from the root */

+	h->next = nil;

+	for(hl = &hubs; *hl != nil; hl = &(*hl)->next)

+		;

+	*hl = h;

 	nhubs++;

 	dprint(2, "%s: %s: hub %#p allocated:", argv0, fn, h);

 	dprint(2, " ports %d pwrms %d max curr %d pwrm %d cmp %d leds %d\n",

-- 

⑨