Add a workaround for VIA EHCI controllers which, under load, signal qTD

completion before they have performed writeback from the overlay qTD.

This condition would exhibit itself as a umass stall that never recovers.

ok dlg@

2 files changed, 37 insertions, 2 deletions

diff --git a/sys/dev/usb/ehci.c b/sys/dev/usb/ehci.c
index 82159709010..dad2e61ca11 100644
--- a/sys/dev/usb/ehci.c
+++ b/sys/dev/usb/ehci.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ehci.c,v 1.37 2005/03/06 05:18:34 pascoe Exp $ */
+/*	$OpenBSD: ehci.c,v 1.38 2005/03/07 11:12:04 pascoe Exp $ */
 /*	$NetBSD: ehci.c,v 1.66 2004/06/30 03:11:56 mycroft Exp $	*/
 
 /*
@@ -155,6 +155,7 @@ Static void		ehci_check_intr(ehci_softc_t *, struct ehci_xfer *);
 Static void		ehci_idone(struct ehci_xfer *);
 Static void		ehci_timeout(void *);
 Static void		ehci_timeout_task(void *);
+Static void		ehci_intrlist_timeout(void *);
 
 Static usbd_status	ehci_allocm(struct usbd_bus *, usb_dma_t *, u_int32_t);
 Static void		ehci_freem(struct usbd_bus *, usb_dma_t *);
@@ -487,6 +488,7 @@ ehci_init(ehci_softc_t *sc)
 	EOWRITE4(sc, EHCI_ASYNCLISTADDR, sqh->physaddr | EHCI_LINK_QH);
 
 	usb_callout_init(sc->sc_tmo_pcd);
+	usb_callout_init(sc->sc_tmo_intrlist);
 
 	lockinit(&sc->sc_doorbell_lock, PZERO, "ehcidb", 0, 0);
 
@@ -687,6 +689,12 @@ ehci_softintr(void *v)
 		ehci_check_intr(sc, ex);
 	}
 
+	/* Schedule a callout to catch any dropped transactions. */
+	if ((sc->sc_flags & EHCIF_DROPPED_INTR_WORKAROUND) &&
+	    !LIST_EMPTY(&sc->sc_intrhead))
+		usb_callout(sc->sc_tmo_intrlist, hz,
+			    ehci_intrlist_timeout, sc);
+
 #ifdef USB_USE_SOFTINTR
 	if (sc->sc_softwake) {
 		sc->sc_softwake = 0;
@@ -926,6 +934,7 @@ ehci_detach(struct ehci_softc *sc, int flags)
 	if (rv != 0)
 		return (rv);
 
+	usb_uncallout(sc->sc_tmo_intrlist, ehci_intrlist_timeout, sc);
 	usb_uncallout(sc->sc_tmo_pcd, ehci_pcd_enable, sc);
 
 	if (sc->sc_powerhook != NULL)
@@ -2511,6 +2520,29 @@ ehci_timeout_task(void *addr)
 	splx(s);
 }
 
+/*
+ * Some EHCI chips from VIA seem to trigger interrupts before writing back the
+ * qTD status, or miss signalling occasionally under heavy load.  If the host
+ * machine is too fast, we we can miss transaction completion - when we scan
+ * the active list the transaction still seems to be active.  This generally
+ * exhibits itself as a umass stall that never recovers.
+ *
+ * We work around this behaviour by setting up this callback after any softintr
+ * that completes with transactions still pending, giving us another chance to
+ * check for completion after the writeback has taken place.
+ */
+void
+ehci_intrlist_timeout(void *arg)
+{
+	ehci_softc_t *sc = arg;
+	int s = splusb();
+
+	printf("ehci_intrlist_timeout\n");
+	usb_schedsoftintr(&sc->sc_bus);
+
+	splx(s);
+}
+
 /************************/
 
 Static usbd_status
diff --git a/sys/dev/usb/ehcivar.h b/sys/dev/usb/ehcivar.h
index bdfde1445b0..8e79b5fd3e4 100644
--- a/sys/dev/usb/ehcivar.h
+++ b/sys/dev/usb/ehcivar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ehcivar.h,v 1.7 2004/12/29 01:52:27 dlg Exp $ */
+/*	$OpenBSD: ehcivar.h,v 1.8 2005/03/07 11:12:04 pascoe Exp $ */
 /*	$NetBSD: ehcivar.h,v 1.12 2001/12/31 12:16:57 augustss Exp $	*/
 
 /*
@@ -92,6 +92,8 @@ typedef struct ehci_softc {
 	bus_space_handle_t ioh;
 	bus_size_t sc_size;
 	u_int sc_offs;			/* offset to operational regs */
+	int sc_flags;			/* misc flags */
+#define EHCIF_DROPPED_INTR_WORKAROUND	0x01
 
 	char sc_vendor[16];		/* vendor string for root hub */
 	int sc_id_vendor;		/* vendor ID for root hub */
@@ -131,6 +133,7 @@ typedef struct ehci_softc {
 	struct lock sc_doorbell_lock;
 
 	usb_callout_t sc_tmo_pcd;
+	usb_callout_t sc_tmo_intrlist;
 
 	device_ptr_t sc_child;		/* /dev/usb# device */