Date: Tue, 30 Aug 2005 20:08:57 +0100 From: Ian Dowse <iedowse@iedowse.com> To: "Eygene A. Ryabinkin" <freebsd@rea.mbslab.kiae.ru> Cc: hackers@freebsd.org, Eugene Grosbein <eugen@kuzbass.ru>, freebsd-usb@freebsd.org Subject: Re: Low umass performance with USB 2.0 ports Message-ID: <200508302009.aa99975@nowhere.iedowse.com> In-Reply-To: Your message of "Tue, 30 Aug 2005 16:50:31 %2B0400." <20050830125031.GA775@rea.mbslab.kiae.ru>
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In message <20050830125031.GA775@rea.mbslab.kiae.ru>, "Eygene A. Ryabinkin" wri
tes:
>>
>> What is filesystem has your USB drive?
> The one I was extensively testing has FAT, but I've checked the UFS2 --
>just a bit better -- 1.8 Mb/second. But you're right -- no wdrains at all.
>> FreeBSD 4.x had very low performance with FAT filesystem,
>> writing process spent lots of time in the wdrain state too.
> Yes, it has. But here the same flash drive gives different results for
>ehci and uhci devices, and the total speed of echi is lower due to wdrains:
>300 Kb/sec versus 500 Kb/sec. And I sometimes write my data to the Windows
>partition with FAT to my home HDD -- it has no wdrains. At least, I've not
>noticed them. For flash I can.
The patch in from the email below may help with the wdrain state -
can you see if it makes any difference?
Ian
Date: Sun, 26 Jun 2005 17:42:44 BST
To: Stefan Walter <sw@gegenunendlich.de>
cc: freebsd-stable@freebsd.org
From: Ian Dowse <iedowse@iedowse.com>
Subject: Re: EHCI: mtools stuck in state 'physrd' or panic
OpenBSD have a workaround for problems with VIA EHCI controllers
that can cause the hanging symptoms you describe. Below is a patch
that implements their change in FreeBSD's driver. Could you try it
to see if it helps?
Thanks,
Ian
Index: sys/dev/usb/ehci.c
===================================================================
RCS file: /dump/FreeBSD-CVS/src/sys/dev/usb/ehci.c,v
retrieving revision 1.14.2.9
diff -u -r1.14.2.9 ehci.c
--- sys/dev/usb/ehci.c 31 Mar 2005 19:47:11 -0000 1.14.2.9
+++ sys/dev/usb/ehci.c 26 Jun 2005 16:21:11 -0000
@@ -155,6 +155,7 @@
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 *);
@@ -491,6 +492,7 @@
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);
@@ -694,6 +696,11 @@
ehci_check_intr(sc, ex);
}
+ /* Schedule a callout to catch any dropped transactions. */
+ if ((sc->sc_flags & EHCI_SCFLG_LOSTINTRBUG) &&
+ !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;
@@ -942,6 +949,7 @@
EOWRITE4(sc, EHCI_USBINTR, sc->sc_eintrs);
EOWRITE4(sc, EHCI_USBCMD, 0);
EOWRITE4(sc, EHCI_USBCMD, EHCI_CMD_HCRESET);
+ usb_uncallout(sc->sc_tmo_intrlist, ehci_intrlist_timeout, sc);
usb_uncallout(sc->sc_tmo_pcd, ehci_pcd_enable, sc);
#if defined(__NetBSD__) || defined(__OpenBSD__)
@@ -2701,6 +2708,30 @@
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();
+
+ DPRINTFN(3, ("ehci_intrlist_timeout\n"));
+ usb_schedsoftintr(&sc->sc_bus);
+
+ splx(s);
+}
+
/************************/
Static usbd_status
Index: sys/dev/usb/ehci_pci.c
===================================================================
RCS file: /dump/FreeBSD-CVS/src/sys/dev/usb/ehci_pci.c,v
retrieving revision 1.14.2.2
diff -u -r1.14.2.2 ehci_pci.c
--- sys/dev/usb/ehci_pci.c 13 Jun 2005 09:00:19 -0000 1.14.2.2
+++ sys/dev/usb/ehci_pci.c 26 Jun 2005 16:21:11 -0000
@@ -303,6 +303,10 @@
return ENXIO;
}
+ /* Enable workaround for dropped interrupts as required */
+ if (pci_get_vendor(self) == PCI_EHCI_VENDORID_VIA)
+ sc->sc_flags |= EHCI_SCFLG_LOSTINTRBUG;
+
/*
* Find companion controllers. According to the spec they always
* have lower function numbers so they should be enumerated already.
Index: sys/dev/usb/ehcivar.h
===================================================================
RCS file: /dump/FreeBSD-CVS/src/sys/dev/usb/ehcivar.h,v
retrieving revision 1.4.2.4
diff -u -r1.4.2.4 ehcivar.h
--- sys/dev/usb/ehcivar.h 22 Mar 2005 00:56:54 -0000 1.4.2.4
+++ sys/dev/usb/ehcivar.h 26 Jun 2005 16:21:11 -0000
@@ -93,6 +93,7 @@
#define EHCI_COMPANION_MAX 8
#define EHCI_SCFLG_DONEINIT 0x0001 /* ehci_init() has been called. */
+#define EHCI_SCFLG_LOSTINTRBUG 0x0002 /* workaround for VIA chipsets */
typedef struct ehci_softc {
struct usbd_bus sc_bus; /* base device */
@@ -149,6 +150,7 @@
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 */
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