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 2:01 PM, Alan Cook wrote:
> In trying to support various speeds with my application, I attempted to change
> the speed and width of Infiniband card using ibportstate.  I had difficulty with
> the reliability of the setting changes working.  I found that I needed to set
> "force_link_speed 0" in /etc/ofed/opensm.conf.  Once that change as made the
> service restarted, I was able to reliably change settings on the cards.
>
> All was well until I changed the card to 2.5 x1.  At this point, I was unable to
> ping the other machine.  Both PCs show that the link is up and active, but I am
> unable to get any communication between the two.  I tried both ping and ibping
> with no success.  I brought the interfaces down and back up, but that did not
> solve the issue.
>
> I have been using the following commands (as root) to adjust the speed and width:
>
> ibportstate -C mlx4_0 -D 0 1 speed [1-7]
> ibportstate -C mlx4_0 -D 0 1 width [1|2]
> ibportstate -C mlx4_0 -D 0 1 reset
>
> I was able to both ping and ibping when using the following speed and width
> configurations:
>
>   2.5 Gbps x4
>   5.0 Gbps x1
>   5.0 Gbps x4
> 10.0 Gbps x1
> 10.0 Gbps x4
>
> The only setting configuration that does not work is the 2.5 x1.
>
> Is there something that I am missing?

What does smpquery portinfo say for both sides of that link ?

-- Hal

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