Re: Unable to Connect Using Active Speed 2.5 Gbps and Active Width of 1

[Hal Rosenstock <hal-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

On 3/28/2011 3:26 PM, Alan Cook wrote:
> Hal Rosenstock<hal@...>  writes:
>>
>> LinkWidthEnabled is 1X or 4X and not just 1X. That's because there's no
>> force_link_width option in OpenSM so I think the width you set is
>> getting overwritten much like the speed was earlier until you discovered
>> force_link_speed 0.
>
> But I see LinkWidthActive set to 1X, which as I understood denoted the width
> currently being used.

Yes as long as a renegotiation occurred after the enabled width was changed.

> If I set LinkWidthActive to 4X, I am able to transfer
> just fine.
>
> Also, I do see LinkWidthEnabled being changed from "1X" to "1X or 4X" (most
> likely by OpenSM as you suggest), but only after the link is up and active.

If it's changed after the link is up and no renegotiation occurs, then 
this is a don't care as you indicate/

> I am able to transfer at 5 Gbps 1X and 10 Gbps 1X, just not 2.5 Gbps 1X.

I don't have a theory for why only that combo would fail. Do you have 
any other HCA types to try ?

>>
>> Also, is this b2b HCAs or is there a switch in the topology ?
>>
>
> It's b2b HCAs, no switch.

I think ibportstate uses combine routing which is problematic if 
directed at HCA.


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