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

From: Hans de Goede
Date: Fri Oct 12 2012 - 10:11:11 EST


Hi,

On 10/11/2012 11:53 PM, Greg Kroah-Hartman wrote:
On Thu, Oct 11, 2012 at 11:37:07PM +0200, 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 whath
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.

Large input transfers certainly do, as they were part of my tests, but
I must admit my test cases seem to not include large output transfers
(my bad).

Thanks for fixing this!

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?

Henrik, Very nice fix, thanks for debugging this.

Hans, any objection to me taking this?

No objections please take it, this patch is:

Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx>

And stating the obvious:

CC: stable@xxxxxxxxxxxxxxx

To be backported to 3.6 only

Thanks & Regards,

Hans
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