From ca63b430b7515c7a0e44e9f77e43a385f5561ce6 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 13 May 2002 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2002-05-13

---
 pc/usbuhci.c | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/pc/usbuhci.c b/pc/usbuhci.c
index 776603824ac069a37726a9baa001f23e7962375d..c28217e6492c94efda38d6a62839a2448c9908a1 100644
--- a/pc/usbuhci.c
+++ b/pc/usbuhci.c
@@ -1071,13 +1071,27 @@ eptinput(void *arg)
 	return e->eof || e->err || qcanread(e->rq);
 }
 
+static int
+isoreadyx(Endptx *x)
+{
+	return x->etd == nil || (x->etd != x->xtd && (x->etd->status & Active) == 0);
+}
+
 static int
 isoready(void *arg)
 {
+	int ret;
+	Ctlr *ctlr;
+	Endpt *e;
 	Endptx *x;
 
-	x = arg;
-	return x->etd == nil || (x->etd != x->xtd && (x->etd->status & Active) == 0);
+	e = arg;
+	ctlr = e->dev->uh->ctlr;
+	x = e->private;
+	ilock(&ctlr->activends);
+	ret = isoreadyx(x);
+	iunlock(&ctlr->activends);
+	return ret;
 }
 
 static long
@@ -1151,13 +1165,13 @@ isoio(Ctlr *ctlr, Endpt *e, void *a, long n, ulong offset, int w)
 				e->off = 0;
 			}else{
 				/* New td, make sure it's ready */
-				isolock = 0;
-				iunlock(&ctlr->activends);
-				while (isoready(x) == 0){
-					sleep(&e->wr, isoready, x);
+				while (isoreadyx(x) == 0){
+					isolock = 0;
+					iunlock(&ctlr->activends);
+					sleep(&e->wr, isoready, e);
+					ilock(&ctlr->activends);
+					isolock = 1;
 				}
-				ilock(&ctlr->activends);
-				isolock = 1;
 				if (x->etd == nil){
 					XPRINT("!");
 					continue;