[openib-general] [query]requirement of 'process_mad' in the HCA driver

[Hal Rosenstock]

On Wed, 2006-12-13 at 22:49, keshetti mahesh wrote:
> thanks for your reply,
> 
> >The driver is needed to obtain the information for the IB node to
> fill
> >in the MADs for response to the SMA query. It may also issue some
> traps.
> >Similarly for PMA as well.
> 
> Do u mean to say that HCA driver is needed to pass the HCA related
> information (like GID, GUID, port_info etc..) to the SMA so that it
> can reply to query(or GET ) MADs.

Yes.

>  Isn't SMA capable of doing the same by using "query_(gid, pkey,
> port)" verbs.

One reason I can think of is that not all the needed information is
available via verbs. I think there are some others as well.

> And final  questions  if it is really required to implement
> 'process_mad' in HCA driver then why it is not specified in the IB
> specifications.

IB spec is architecture not implementation.

> Whose duty is this (replying to query MADs) according to the IB
> psec.s(its duty of SMA right?)

Depends on the MAD but if you are referring to the SMA queries, then yes
it is the SMA's responsibility.

> I have observed that process_mad is not implemented in the IBM's eHCA
> driver. what is the case with it?

With eHCA, QP0 is not exposed to the host (at least currently) and the
SMA is totally implemented in firmware.

> PS: I am considering only SMA in the host s/w here.

This is a design choice.

-- Hal

> regards,
> K.Mahesh.
> 
> 
> 
> 
> Hal Rosenstock <halr at voltaire.com> wrote:
>         On Wed, 2006-12-13 at 01:55, keshetti mahesh wrote:
>         > Hello all,
>         > 
>         > I want to know from u people that isi it necessary to
>         implement the
>         > process_mad for a HCA.
>         > 
>         > After looking into the implementations of process_mad in
>         ipath and
>         > mthca drivers i have fount that they are used to reply the
>         MADs with
>         > port_info,gid_info,sm_info etc..
>         > 
>         > But isn't it handled by SMA in the host......
>         
>         The SMA can either be in the host on in firmware (as is
>         typical with the
>         Mellanox silicon).
>         
>         > i am little bit confused now .
>         > please just whether it is required to implement process_mad
>         (suppose)
>         > for new HCA driver....
>         
>         It is. For an example of a host (software SMA), see
>         drivers/infiniband/hw/ipath/ipath_mad.c
>         
>         > if it is required why?
>         
>         The driver is needed to obtain the information for the IB node
>         to fill
>         in the MADs for response to the SMA query. It may also issue
>         some traps.
>         Similarly for PMA as well.
>         
>         -- Hal
>         
>         > Please CC your replies to me.
>         > 
>         > regards,
>         > K.Mahesh.
>         > 
>         > 
>         > 
>         > 
>         > 
>         > 
>         > 
>         >
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