Ongoing battle with umass(4) and xhci(4)

[Brandon Gooch]

On Mon, Mar 12, 2012 at 3:15 AM, Hans Petter Selasky <hselasky at c2i.net> wrote:
>>
>> Is there something fishy happening between the USB stack and CAM? hmmm...
>>
>
> No,
>
> It is not the CAM layer this time, though there are some bugs there too.
>
>
> In the beginning of the log I see that in the successful case we receive a
> stall event:
>
> -xhci_check_transfer: slot=1 epno=3 remainder=13 status=6
> -xhci_check_transfer: TD is last
> -xhci_cmd_stop_ep:
> -xhci_check_command: Received command event
> -xhci_configure_reset_endpoint: Could not stop endpoint 3
> -xhci_cmd_reset_ep:
> -xhci_check_command: Received command event
> -xhci_cmd_set_tr_dequeue_ptr:
> -xhci_check_command: Received command event
> -xhci_cmd_evaluate_ctx:
> -xhci_check_command: Received command event
> -xhci_cmd_configure_ep:
> -xhci_check_command: Received command event
> -xhci_configure_reset_endpoint: Could not configure endpoint 3
> -xhci_ep_clear_stall:
> -xhci_device_generic_enter:
> -xhci_setup_generic_chain_sub: NTRB=1
> -xhci_setup_generic_chain_sub: LINK=0x82883180
> -xhci_setup_generic_chain_sub: NTRB=1
> -xhci_setup_generic_chain_sub: LINK=0x82883000
> -xhci_setup_generic_chain: first=0xffffff8460883300 last=0xffffff8460883180
> -xhci_device_generic_start:
> -xhci_transfer_insert: qh_pos = 1
> -xhci_check_transfer: slot=1 epno=1 remainder=0 status=1
> -xhci_check_transfer: slot=1 epno=1 remainder=0 status=1
> -xhci_check_transfer: Following next TD
> -xhci_check_transfer: slot=1 epno=1 remainder=0 status=1
> -xhci_check_transfer: slot=1 epno=1 remainder=0 status=1
> -xhci_check_transfer: TD is last
>
>
> This is not received in the failing case.
>
> Maybe this indicates a lost interrupt or something like that?
>
> In /sys/dev/usb/controller/xhci.c
>
> static void
> xhci_interrupt_poll(struct xhci_softc *sc)
>
> Add a printf:
>
>                if (i == XHCI_MAX_EVENTS) {
>                        i = 0;
>                        j ^= 1;
>
>                        /* check for timeout */
>                        if (!--t) {
>                                +                       printf("XHCI: Timeout\n");
>                                break;
>                                }
>                }
>
>
> See if what happens.
>
> Also change the xhci.c code to call
>
> xhci_interrupt_poll() two times instead of one.
>
>
> --HPS

Unfortunately, the condition was never reached.

I've started trying to dtrace xhci(4) function boundaries, and, well
there's a lot of recursion with xhci_interrupt_poll().  However, I
never see that function called from xhci_do_poll(), which is called
from xhci_interrupt() (to "catch any lost interrupts" according to the
comment).

You may have already told me this, but what does "Down reving Protocol
Version from 2 to 0?" in the success case on my system?  Is this the
USB protocol which is "down rev'ed"?  If so, what USB level is this
flash drive running at?

-Brandon