> On 29.9.2019 9.07, Peter Chen wrote:
> > On some situations, the software handles TRB events slower than adding
> > TRBs, then xhci_handle_event can't return zero long time, the xHC will
> > consider the event ring is full, and trigger "Event Ring Full" error,
> > but in fact, the software has already finished lots of events, just no
> > chance to update ERDP (event ring dequeue pointer).
> >
> > In this commit, we force update ERDP if half of TRBS_PER_SEGMENT
> > events have handled to avoid "Event Ring Full" error.
> >
> > Signed-off-by: Peter Chen <peter.c...@nxp.com>
> > ---
> > Changes for v2:
> > - If current ERDP value is the same with intended written one,
> > give up this written.
> >
> > drivers/usb/host/xhci-ring.c | 62 ++++++++++++++++++++++++++----------
> > 1 file changed, 45 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci-ring.c
> > b/drivers/usb/host/xhci-ring.c index e220bcbee173..2c0a15c3b3a7 100644
> > --- a/drivers/usb/host/xhci-ring.c
> > +++ b/drivers/usb/host/xhci-ring.c
> > @@ -2737,6 +2737,44 @@ static int xhci_handle_event(struct xhci_hcd *xhci)
> > return 1;
> > }
> >
> > +/*
> > + * Update Event Ring Dequeue Pointer:
> > + * - When all events have finished
> > + * - To avoid "Event Ring Full Error" condition */ static void
> > +xhci_update_erst_dequeue(struct xhci_hcd *xhci,
> > + union xhci_trb *event_ring_deq)
> > +{
> > + u64 temp_64;
> > + dma_addr_t deq;
> > +
> > + temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
> > + /* If necessary, update the HW's version of the event ring deq ptr. */
> > + if (event_ring_deq != xhci->event_ring->dequeue) {
> > + deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
> > + xhci->event_ring->dequeue);
> > + if (deq == 0)
> > + xhci_warn(xhci, "WARN something wrong with SW event "
> > + "ring dequeue ptr.\n");
> > +
> > + /*
> > + * Per 4.9.4, Software writes to the ERDP register shall
> > + * always advance the Event Ring Dequeue Pointer value.
> > + */
> > + if ((temp_64 & (u64) ~ERST_PTR_MASK) ==
> > + ((u64) deq & (u64) ~ERST_PTR_MASK))
> > + return;
> > +
> > + /* Update HC event ring dequeue pointer */
> > + temp_64 &= ERST_PTR_MASK;
> > + temp_64 |= ((u64) deq & (u64) ~ERST_PTR_MASK);
> > + }
> > +
> > + /* Clear the event handler busy flag (RW1C) */
> > + temp_64 |= ERST_EHB;
> > + xhci_write_64(xhci, temp_64, &xhci->ir_set->erst_dequeue); }
> > +
> > /*
> > * xHCI spec says we can get an interrupt, and if the HC has an error
> > condition,
> > * we might get bad data out of the event ring. Section 4.10.2.7
> > has a list of @@ -2748,9 +2786,9 @@ irqreturn_t xhci_irq(struct usb_hcd
> > *hcd)
> > union xhci_trb *event_ring_deq;
> > irqreturn_t ret = IRQ_NONE;
> > unsigned long flags;
> > - dma_addr_t deq;
> > u64 temp_64;
> > u32 status;
> > + int event_loop = 0;
> >
> > spin_lock_irqsave(&xhci->lock, flags);
> > /* Check if the xHC generated the interrupt, or the irq is shared
> > */ @@ -2804,24 +2842,14 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
> > /* FIXME this should be a delayed service routine
> > * that clears the EHB.
> > */
> > - while (xhci_handle_event(xhci) > 0) {}
> > -
> > - temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
> > - /* If necessary, update the HW's version of the event ring deq ptr. */
> > - if (event_ring_deq != xhci->event_ring->dequeue) {
> > - deq = xhci_trb_virt_to_dma(xhci->event_ring->deq_seg,
> > - xhci->event_ring->dequeue);
> > - if (deq == 0)
> > - xhci_warn(xhci, "WARN something wrong with SW event "
> > - "ring dequeue ptr.\n");
> > - /* Update HC event ring dequeue pointer */
> > - temp_64 &= ERST_PTR_MASK;
> > - temp_64 |= ((u64) deq & (u64) ~ERST_PTR_MASK);
> > + while (xhci_handle_event(xhci) > 0) {
> > + if (event_loop++ < TRBS_PER_SEGMENT / 2)
> > + continue;
> > + xhci_update_erst_dequeue(xhci, event_ring_deq);
> > + event_loop = 0;
> > }
> >
> > - /* Clear the event handler busy flag (RW1C); event ring is empty. */
> > - temp_64 |= ERST_EHB;
> > - xhci_write_64(xhci, temp_64, &xhci->ir_set->erst_dequeue);
> > + xhci_update_erst_dequeue(xhci, event_ring_deq);
> > ret = IRQ_HANDLED;
> >
> > out:
> >
>
> This should work, adding to queue
Thanks, I have tested these days, no issue has found so far.
Peter
