[openib-general] Unusable QP's on CM established connections from gen2 client to gen1 server.

[Sean Hefty]

Bub Thomas wrote:
> Setting the hop_limit from 64 down to 0 or 1 solved the problem. :-)
> Don't ask me where I got that hop_limit from, it must have been an
> example I found somewhere.
> Can you explain why that hop_limit/is_global makes a difference in
> communication between gen1 and gen2? Does the counterpart need to have
> the same hop_limit?

The gen2 stack uses a hop_limit > 0 to indicate that global routing is being 
used.  If the hop_limit is > 0, then the global routing information must be valid.

> The path record values I use are queried from the OSM using a
> SERVICE_RECORD query followed by a path record query.
> I'm not using any alternate path record values, is this critical?

Everything is supposed to work with the path records returned from the SM.  I 
was wondering if you were querying for the path record, modifying the returned 
value, or creating a path record yourself.

>     path_record.packet_life_time = 0;

I would set this higher (maybe between 12-20, with: 18 = 1 second, 19 = 2 
seconds, 20 = 4 seconds, etc.)