usb: fix ehci isochronous "in" split transactions

For "in" transactions, the "Total Bytes to Transfer" field in
the siTD is decremented by the controller by the actual transfer
size, so what remains in the field is the residue number of bytes.

Also, handle restart when we get a zero byte read on a isochronous
"in" endpoint in devusb itself (removing the restart code for
xhci drivers).

This fixes audio recording with a usb1.1 audio device connected
to ehci controller.

3 files changed, 30 insertions, 26 deletions

diff --git a/sys/src/9/port/devusb.c b/sys/src/9/port/devusb.c
index e395df265..beb55055c 100644
--- a/sys/src/9/port/devusb.c
+++ b/sys/src/9/port/devusb.c
@@ -1199,19 +1199,22 @@ usbread(Chan *c, void *a, long n, vlong offset)
 		error(Enotconf);
 	case Tctl:
 		nr = rhubread(ep, a, n);
-		if(nr >= 0){
-			n = nr;
+		if(nr >= 0)
 			break;
-		}
 		/* else fall */
 	default:
 		ddeprint("\nusbread q %#x fid %d cnt %ld off %lld\n",q,c->fid,n,offset);
-		n = ep->hp->epread(ep, a, n);
+	Again:
+		nr = ep->hp->epread(ep, a, n);
+		if(nr == 0 && ep->ttype == Tiso){
+			tsleep(&up->sleep, return0, nil, 2*ep->pollival);
+			goto Again;
+		}
 		break;
 	}
 	poperror();
 	putep(ep);
-	return n;
+	return nr;
 }
 
 /*
diff --git a/sys/src/9/port/usbehci.c b/sys/src/9/port/usbehci.c
index 1d2dd6d49..f89804415 100644
--- a/sys/src/9/port/usbehci.c
+++ b/sys/src/9/port/usbehci.c
@@ -1365,7 +1365,7 @@ isohsinterrupt(Ctlr *ctlr, Isoio *iso)
 	ctlr->nisointr++;
 	ddiprint("isohsintr: iso %#p: tdi %#p tdu %#p\n", iso, tdi, iso->tdu);
 	if(iso->state != Qrun && iso->state != Qdone)
-		panic("isofsintr: iso state");
+		panic("isohsintr: iso state");
 	if(ehcidebug > 1 || iso->debug > 1)
 		isodump(iso, 0);
 
@@ -1394,6 +1394,8 @@ isohsinterrupt(Ctlr *ctlr, Isoio *iso)
 			tdi->ndata = 0;
 
 		if(tdi->next == iso->tdu || tdi->next->next == iso->tdu){
+			diprint("overrun iso %#p tdi %#p tdu %#p\n", iso, tdi, iso->tdu);
+
 			memset(iso->tdu->data, 0, iso->tdu->mdata);
 			itdinit(ctlr, iso, iso->tdu);
 			iso->tdu = iso->tdu->next;
@@ -1402,13 +1404,13 @@ isohsinterrupt(Ctlr *ctlr, Isoio *iso)
 		tdi = tdi->next;
 		coherence();
 	}
-	ddiprint("isohsintr: %d frames processed\n", nframes);
+	ddiprint("isohsintr: %d frames processed\n", i);
 	if(i == nframes){
 		tdi->csw[0] |= Itdioc;
 		coherence();
 	}
-	iso->tdi = tdi;
 	coherence();
+	iso->tdi = tdi;
 	if(isocanwrite(iso) || isocanread(iso)){
 		diprint("wakeup iso %#p tdi %#p tdu %#p\n", iso,
 			iso->tdi, iso->tdu);
@@ -1444,20 +1446,24 @@ isofsinterrupt(Ctlr *ctlr, Isoio *iso)
 		err = stdi->csw & Stderrors;
 		if(err == 0){
 			iso->nerrs = 0;
-			if(iso->tok == Tdtokin)
-				stdi->ndata = (stdi->csw>>Stdlenshift)&Stdlenmask;
-		}else if(iso->nerrs++ > iso->nframes/2){
-			if(iso->err == nil){
-				iso->err = serrmsg(err);
-				diprint("isofsintr: tdi %#p error %#ux %s\n",
-					stdi, err, iso->err);
-				diprint("ctlr load %uld\n", ctlr->load);
+			if(iso->tok == Tdtokin){
+				ulong residue = (stdi->csw>>Stdlenshift)&Stdlenmask;
+				stdi->ndata = residue < stdi->ndata ? stdi->ndata - residue : 0;
+				diprint("isofsintr: tdi %#p ndata %lud, mdata %lud\n", stdi, stdi->ndata, stdi->mdata);
+			}
+		}else {
+			diprint("isofsintr: tdi %#p error %#ux %s\n", stdi, err, serrmsg(err));
+			if(iso->nerrs++ > iso->nframes/2){
+				if(iso->err == nil){
+					iso->err = serrmsg(err);
+					diprint("ctlr load %uld\n", ctlr->load);
+				}
 			}
 			stdi->ndata = 0;
-		}else
-			stdi->ndata = 0;
-
+		}
 		if(stdi->next == iso->stdu || stdi->next->next == iso->stdu){
+			diprint("overrun iso %#p tdi %#p tdu %#p\n", iso, stdi, iso->stdu);
+
 			memset(iso->stdu->data, 0, iso->stdu->mdata);
 			sitdinit(ctlr, iso, iso->stdu);
 			iso->stdu = iso->stdu->next;
@@ -1466,13 +1472,13 @@ isofsinterrupt(Ctlr *ctlr, Isoio *iso)
 		coherence();
 		stdi = stdi->next;
 	}
-	ddiprint("isofsintr: %d frames processed\n", nframes);
+	ddiprint("isofsintr: %d frames processed\n", i);
 	if(i == nframes){
 		stdi->csw |= Stdioc;
 		coherence();
 	}
-	iso->stdi = stdi;
 	coherence();
+	iso->stdi = stdi;
 	if(isocanwrite(iso) || isocanread(iso)){
 		diprint("wakeup iso %#p tdi %#p tdu %#p\n", iso,
 			iso->stdi, iso->stdu);
diff --git a/sys/src/9/port/usbxhci.c b/sys/src/9/port/usbxhci.c
index 4c2b60a3b..bdaf968ed 100644
--- a/sys/src/9/port/usbxhci.c
+++ b/sys/src/9/port/usbxhci.c
@@ -1338,7 +1338,6 @@ isoread(Ep *ep, uchar *p, long n)
 	}
 	µ = io->period;
 	ctlr = ep->hp->aux;
-Again:
 	if(needrecover(ctlr))
 		error(Erecover);
 
@@ -1386,10 +1385,6 @@ Again:
 	io->frame = i;
 
 	*io->ring->doorbell = io->ring->id;
-	if(p == s){
-		tsleep(&up->sleep, return0, nil, 5);
-		goto Again;
-	}
 	qunlock(io);
 	poperror();