[ofa-general] mthca max_sge value... ugh.

[Jack Morgenstein]

On Sunday 18 May 2008 19:04, Roland Dreier wrote:
> But can you point me to the place in the IB spec where it requires all
> sge limits to be no bigger
> than the returned max_sge value?
> 
Its not mentioned specifically, but certainly is strongly implied.

1. Section 11.2.1.2 -- Query HCA:
• The maximum number of scatter/gather entries per Work Re-
  quest supported by this HCA, for all Work Requests other
  than Reliable Datagram Receive Queue Work Requests.

This certainly implies that the create verb should not return
a number of scatter-gather entries greater than the max_sge value
(which is the max value supported by this HCA).
Otherwise, why have a max_sge value returned by Query HCA?  What use
would it serve?

Furthermore, how can the HCA return an sge value
in Create QP which exceeds the max_sge value returned by Query HCA? If
it does, the sge value in Create QP should be the one returned in
Query HCA!

- Jack