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Code Issues Releases Activity

Work around a problem seen on VIA EHCI controllers where occasionally

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an interrupt appears to occur before the transfer has been marked
as completed. This caused umass transfers to get stuck, especially
when writing large files. The workaround sets up a timer that
rechecks for missed completed transfers if some operations are still
pending. Other suggested workarounds, such as performing a PCI read
immediately after acknowledging the interrupts, do not appear to
help.

Obtained from:	OpenBSD
This commit is contained in:
Ian Dowse 2006-01-15 21:03:19 +00:00
parent df3e5efa87
commit afcb6f8261
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=154407
3 changed files with 38 additions and 0 deletions
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32
sys/dev/usb/ehci.c
View File

@ -153,6 +153,7 @@ 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 *);
@ -489,6 +490,7 @@ 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);
@ -692,6 +694,12 @@ ehci_softintr(void *v)
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 / 5, ehci_intrlist_timeout,
sc);
#ifdef USB_USE_SOFTINTR
if (sc->sc_softwake) {
sc->sc_softwake = 0;
@ -942,6 +950,7 @@ ehci_detach(struct ehci_softc *sc, int flags)
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__)
@ -2700,6 +2709,29 @@ 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();
DPRINTFN(3, ("ehci_intrlist_timeout\n"));
usb_schedsoftintr(&sc->sc_bus);
splx(s);
}
/************************/
Static usbd_status

4
sys/dev/usb/ehci_pci.c
View File

@ -373,6 +373,10 @@ ehci_pci_attach(device_t self)
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.

2
sys/dev/usb/ehcivar.h
View File

@ -94,6 +94,7 @@ struct ehci_soft_islot {
#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 */
@ -153,6 +154,7 @@ typedef struct ehci_softc {
struct lock sc_doorbell_lock;
usb_callout_t sc_tmo_pcd;
usb_callout_t sc_tmo_intrlist;
#if defined(__NetBSD__) || defined(__OpenBSD__)
device_ptr_t sc_child; /* /dev/usb# device */