Re: REGRESSION: usbdevfs:Use-scatter-gather-lists-for-large-bulk-transfers

From: Peter Stuge
Date: Thu Oct 11 2012 - 17:40:54 EST


Henrik Rydberg wrote:
> Hi Hans,
>
> > Oh what fun (not). The best way to figure out what really is going
> > on is to get some usb level traces. Note my first hunch is that what
> > you're seeing is a device firmware bug, as this patch together with
> > a new libusb (which you seem to also have) will make bulk transfers
> > run slightly faster, which might be just enough to overwhelm your
> > device ...
>
> Or, the large bulk transfer actually never worked in the first place.
> The list you gave me seemed boringly long, so I read the patch more
> closely instead. The fix below is the result. Greg, will you please
> take it through your tree?
>
> Thanks,
> Henrik
>
> From 40b70394747eea51fdd07cc8213dd6afd24b1b30 Mon Sep 17 00:00:00 2001
> From: Henrik Rydberg <rydberg@xxxxxxxxxxx>
> Date: Thu, 11 Oct 2012 23:27:04 +0200
> Subject: [PATCH] usbdevfs: Fix broken scatter-gather transfer
>
> The recently introduced handling of large bulk transfers is completely
> broken; the same user page is read over and over again. Fixed with
> this patch.
>
> Cc: stable@xxxxxxxxxx
> Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>

Acked-by: Peter Stuge <peter@xxxxxxxx>
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