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

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 24.07.2015 18:33, Arkadiusz Miskiewicz wrote:
> 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 Miśkiewicz <arekm@maven.pl>
> 
> Thanks!
> 
> ps. please push to stable@, too
> 

Patch sent forward, added Tested-by and stable tags

Thanks
- Mathias