Re: PCI passthrough issue

[Jean Baptiste Favre <xen-devel@jbfavre.org>]

Le 04/02/2011 14:50, Ian Campbell a écrit :
> On Fri, 2011-02-04 at 13:15 +0000, Jean Baptiste Favre wrote:
> 
>>
>>>> What is a bit strange here is that I don't any more the KERN_CRIT printk
>>>> message.
>>>> Could be a false positive ?
>>>
>>> Worth bearing in mind, lets see what the next test run produces.
>> Seems that I got this messge only with copybreak=0.
>> With default value (128), no such message
>>
>> More, with copybreak=0, all packets are dropped (even a ping with
>> default packet size is dropped. Same with ping -s1)
> 
> Hang on, I thought you previously said copybreak=0 made everything work
> ok. If that isn't definitely the case then we may be following a red
> herring.
That's something I'm investigating.
Under Debian, copybreak=0 solve the problem
Under OpenWRT, copybreak=0 + patch breaks. Will try without patch.

> Are you saying that copybreak=0 + this patch breaks? That would be very
> surprising since the patch doesn't cause any flow control differences.
> 
> Perhaps there is some difference between your self-built kernels and the
> Debian kernels you started with? Perhaps you should try the self built
> kernel with no patches, just to confirm it behaves the same as the
> Debian kernels?
Under Debian, I use 2.6.37 from experimental
Under OpenWRT, use legacy 2.6.37, build env applies patches for OpenWRT
and compile.

OpenWRT provides complete build env, as I still have problem compiling
Debian 32bits kernel from 64bits env. That's why I switched back to
openWRT for testing.


>>> Thanks.
>>>
>>> Please gather the tcpdump's too.
>> Both tcpdump from GW and domU are Attached.
> 
> Were these collected with or without patches? With or without ethtool -K
> options? With or without copybreak?
> 
> Please try and be explicit about everything you post, there are lots of
> variables in the air.
OK, sorry. Will redo all tests

Regards,
JB