Re: xhci_hcd 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD ep_index 2 comp_code 1

From: Arkadiusz Miskiewicz
Date: Fri Jul 24 2015 - 11:33:29 EST


On Friday 24 of July 2015, Mathias Nyman wrote:
> On 24.07.2015 14:59, Mathias Nyman wrote:
> > On 22.07.2015 17:12, Arkadiusz Miskiewicz wrote:
> >> On Tuesday 21 of July 2015, Mathias Nyman wrote:
> >>> On 20.07.2015 23:13, Arkadiusz Miskiewicz wrote:
> >>>> On Saturday 18 of July 2015, Arkadiusz Miskiewicz wrote:
> >>>>> Hi.
> >>>>>
> >>>>> I'm on 4.2.0-rc2-00077-gf760b87 kernel and while trying to copy some
> >>>>> file from usb storage (sata disk behind sata-usb bridge or pendrive;
> >>>>> hapens in
> >>>>
> >>>>> both cases) copying process hangs just early after start with:
> >>>> Looks like suspend & resume is enough. Reloading bluetooth firmware
> >>>> done by kernel triggers problem:
> >>>>
> >>>> [ 106.302783] rtc_cmos 00:02: System wakeup disabled by ACPI
> >>>> [ 106.313280] PM: resume of devices complete after 3003.032 msecs
> >>>> [ 106.314079] Restarting tasks ... done.
> >>>> [ 106.326434] Bluetooth: hci0: read Intel version: 370710018002030d00
> >>>> [ 106.330422] Bluetooth: hci0: Intel Bluetooth firmware file:
> >>>> intel/ibt-hw-37.7.10-fw-1.80.2.3.d.bseq [ 106.398223] xhci_hcd
> >>>> 0000:00:14.0: ERROR Transfer event TRB DMA ptr not part of current TD
> >>>> ep_index 0 comp_code 1
> >
> > Thanks for the logs, They show that the error is related to transfer
> > descriptors that wrap around on the endpoint ring buffer by exactly one
> > transfer block.
> >
> > I don't know yet why this happens, and I might need some help running
> > additional debug patches to solve this. I'll take a more in depth look
> > at the code one more time first.
>
> I think I found something, The recent ring segment size increase exposed an
> off by one error that has been in the driver for a long time. But you need
> to be unlucky and have your memory pages allocated in a specific order to
> trigger it.
>
> small fix, looks like this:
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 94416ff..77da8fe 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -82,7 +82,7 @@ dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg,
> return 0;
> /* offset in TRBs */
> segment_offset = trb - seg->trbs;
> - if (segment_offset > TRBS_PER_SEGMENT)
> + if (segment_offset > TRBS_PER_SEGMENT - 1)
> return 0;
> return seg->dma + (segment_offset * sizeof(*trb));
> }
>
>
> Patch attached, could you try it out?

Works fine with this patch, so:

Tested-by: Arkadiusz MiÅkiewicz <arekm@xxxxxxxx>

Thanks!

ps. please push to stable@, too

>
> Thanks
> -Mathias

--
Arkadiusz MiÅkiewicz, arekm / ( maven.pl | pld-linux.org )
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