[openib-general] Re: [PATCH] [mthca]: fixed fields in query_port

[Hal Rosenstock]

On Sun, 2005-10-02 at 03:30, Jack Morgenstein wrote:
> On Sat, Oct 01, 2005 at 11:05:27PM +0300, Roland Dreier wrote:
> > In fact is there any reason to have the max_vl_num field be returned
> > from the query_port method?  I don't see anything sensible a consumer
> > can do with the value, and I would think consumers should just be
> > using service levels rather than worrying about the next hop VL.  So
> > maybe we should just delete the field entirely.
> > 
> 
> I agree.  That value is only of interest to the SM, for use in SL-to-VL mapping
> (IB Spec 3.5.7) -- and the SM obtains this value via a MAD query.  Applications
> should use the SL field in packets for specifying a QoS (in the future)-- and 
> should not even be aware of VL's.
> 
> Anyone else have an opinion?

A diagnostics application could use this. Not sure if that is sufficient
justification to keep this in. This value can be retrieved via an SA
query or thorugh SM MADs as long as the protection level is low enough.

-- Hal