[PATCH 0/1] mv643xx_eth: Disable TSO by default

Ezequiel Garcia ezequiel at vanguardiasur.com.ar
Fri May 29 06:07:45 PDT 2015

On 05/29/2015 03:16 AM, Dr. Uwe Meyer-Gruhl wrote:
>> On Wed, Nov 05, 2014 at 08:39:26AM +0000, Ian Campbell wrote:
>>> On Tue, 2014-11-04 at 15:20 +0100, Karl Beldan wrote:
>>>> On Sat, Nov 01, 2014 at 12:30:19PM -0300, Ezequiel Garcia wrote:
>>>>> Several users ([1], [2]) have been reporting data corruption
>>>>> with TSO on Kirkwood platforms (i.e. using the mv643xx_eth
>>>>> driver).
>>>>> Until we manage to find what's causing this, this simple patch 
>>>>> will make
>>>>> the TSO path disabled by default. This patch should be queued
> for stable,
>>>>> fixing the TSO feature introduced in v3.16.
>>>>> The corruption itself is very easy to reproduce: checkingmd5sum on
>>>>> a mounted
>>>>> NFS directory gives a different result each time. Same tests  using
>>>>> the mvneta
>>>>> driver (Armada 370/38x/XP SoC) pass with no issues.
>>>>> Frankly, I'm a bit puzzled about this, and so any ideas ordebugging
>>>>> hints
>>>>> are well received.
>>>> Hi,
>>>> Can you try this :
>>> It fixes things for me, thanks!
>>> Tested-by: Ian Campbell <ijc at hellion.org.uk>
>> Good thing, thanks for your feedbak Ian !
>> Karl --
> That would be a good thing - although: Neither the patch to disable TSO
> altogether nor the one that fixes the underlying problem actually made
> it to the official kernel source tree, so it is still present in all
> kernels > 3.16 - I just stumbled over this in the current 4.0.4 version.
> The fixes in the thread
> http://marc.info/?l=linux-netdev&m=141517941900547&w=2 are not
> applicable any more to the current driver from the 4.0 kernel, as the
> whole respective logic seems to have been changed meanwhile, sadly
> without fixing the problem. Disabling TSO completely still works, though.
> Can someone in the know please suggest a working fix to the kernel
> maintainers, preferably one that does not resort to disable TSO?

Hello Uwe,

Thanks for reporting. There wasn't any patch left behind. The above fix
was merged (and applied to the stable tree) as this commit:

commit 2c2a9cbd64387d6b70ac5db013e9bfe9412c7354
Author: Karl Beldan <karl.beldan at rivierawaves.com>
Date:   Wed Nov 5 15:32:59 2014 +0100

    net: mv643xx_eth: reclaim TX skbs only when released by the HW

Can you explain in detail what sort of problem are you running into,
which kernel version are you using, etc.?
Ezequiel Garcia, VanguardiaSur

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