Re: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 13

[Kai-Heng Feng <kai.heng.feng@canonical.com>]

> On Nov 22, 2019, at 20:17, Mathias Nyman <mathias.nyman@linux.intel.com> wrote:

[snipped]

> 
> The event ring is already overwritten with new events when dumped.
> 
> Could you apply the code below, it will dump both the endpoint transfer ring
> and the event ring at the right moment:

The log is quite large so I pasted it here:
https://pastebin.ubuntu.com/p/wWpS8ctNrb/

Kai-Heng

> 
> Attached as a patch as well.
> 
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 620846f30b4f..a1a9a408c479 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -201,6 +201,31 @@ void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring)
>  * @more_trbs_coming:  Will you enqueue more TRBs before calling
>  *                     prepare_transfer()?
>  */
> +
> +static int xhci_dump_ring(struct xhci_hcd *xhci, struct xhci_ring *ring)
> +{
> +       struct xhci_segment     *seg;
> +       dma_addr_t              dma;
> +       union xhci_trb          *trb;
> +       int                     i, j;
> +
> +       seg = ring->first_seg;
> +
> +       for (i = 0; i < ring->num_segs; i++) {
> +               for (j = 0; j < TRBS_PER_SEGMENT; j++) {
> +                       trb = &seg->trbs[j];
> +                       dma = seg->dma + j * sizeof(*trb);
> +                       xhci_err(xhci, "%pad: %s\n", &dma,
> +                                xhci_decode_trb(le32_to_cpu(trb->generic.field[0]),
> +                                                le32_to_cpu(trb->generic.field[1]),
> +                                                le32_to_cpu(trb->generic.field[2]),
> +                                                le32_to_cpu(trb->generic.field[3])));
> +               }
> +               seg = seg->next;
> +       }
> +       return 0;
> +}
> +
> static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring,
>                        bool more_trbs_coming)
> {
> @@ -2318,6 +2343,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
>        u32 trb_comp_code;
>        int td_num = 0;
>        bool handling_skipped_tds = false;
> +       static unsigned int err_cnt;
>         slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
>        ep_index = TRB_TO_EP_ID(le32_to_cpu(event->flags)) - 1;
> @@ -2579,6 +2605,12 @@ static int handle_tx_event(struct xhci_hcd *xhci,
>                                trb_in_td(xhci, ep_ring->deq_seg,
>                                          ep_ring->dequeue, td->last_trb,
>                                          ep_trb_dma, true);
> +                               if (err_cnt++ == 5) {
> +                                       xhci_err(xhci, "EVENT RING:\n");
> +                                       xhci_dump_ring(xhci, xhci->event_ring);
> +                                       xhci_err(xhci, "ENDPOINT RING:\n");
> +                                       xhci_dump_ring(xhci, ep_ring);
> +                               }
>                                return -ESHUTDOWN;
>                        }
> <0001-xhci-dump-event-ring-and-endpoint-ring-if-TRB-not-fo.patch>