Re: [PATCH 3.12 033/118] usb: xhci: Link TRB must not occur within a USB payload burst

Mark Lord
2014-01-02T21:01:39Z

On 14-01-02 02:15 PM, Sarah Sharp wrote:
> On Tue, Dec 31, 2013 at 12:40:16PM -0800, walt wrote:
..
>> Unfortunately this patch causes a regression when copying large files to my
>> outboard USB3 drive. (Nothing at all to do with networking.)
>>
>> When I try to copy a large (20GB) file to the USB3 drive, the copy dies after
>> about 7GB, the ext4 journal aborts and the drive is remounted read-only.
>>
>> This bug is 100% reproducible (always pretty close to 7GB) and reverting this
>> patch completely fixes the problem.
>
> Ok, I had feared that would be a consequence of this patch. I think the
> problem is that the usb-storage driver submitted an URB with more
> scatter-gather entries than would fit on the ring segment, the xHCI
> driver rejected the URB with -ENOMEM, and the SCSI core eventually gave
> up on the SCSI command.

Is there not a block layer / scheduler tunable for max sg entries or something?
--
Mark Lord
Real-Time Remedies Inc.
mlord@pobox.com