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

From: Sarah Sharp
Date: Tue Jan 07 2014 - 16:27:51 EST

On Tue, Jan 07, 2014 at 01:58:32PM +0000, David Laight wrote:
> The dmesg contains:
> [ 538.728064] EXT4-fs warning (device dm-0): ext4_end_bio:316: I/O error writing to inode 23330865 (offset 0 size 8388608 starting block 812628)
> An 8MB transfer will need at least 128 ring entries (TRB) even if the request
> is a single contiguous memory block.
> Are you using the patch that increases the ring size from 64 to 256?

It's likely that the block layer is breaking up the EXT4 write into
several transfers, since usb-storage limits overall transfer size to
120 KB. In any case, I added more debugging in the last patch to print
the number of TRBs necessary. That way we can verify the patch to limit
the number of scatter-gather list entries is working.

Sarah Sharp
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