Dual-rate transceivers with ixgbe?

[Juli Mallett]

On Thu, Jun 10, 2010 at 12:04, Alexander Sack <pisymbol at gmail.com> wrote:
> However, would it be possible to please make this a kenv tunable in
> the driver?  Its kinda stupid I have to recompile to add a SFP.  It
> can certainly be an unsupported feature by you.

This is a good idea, but asking Jack to commit something that goes
against Intel's wishes and which he's not going to support is probably
a losing strategy.  Whether he minds someone else committing might be
another story :)

One thing that the base driver probably ought to do is not fail in
attach if there's an unrecognized SFP+ module.  Since we get
interrupts on module change (although this doesn't seem to always work
*entirely* right in the stock sources, mostly wrt stored values of
AUTOC and the like) it should be possible to bring the interface up
with the unsupported (and disabled) SFP+ module and do the SFP+ module
probing we already do on hot-swap.

> Patch attached.  Tested with CURRENT driver on a 7.2-amd64-release
> machine.  If you set the tunable to 1, ixgbe loads without issue.  If
> you leave it to zero (default), it will not attach to unsupported
> SFPs.

If you're going to do this, you ought to support SFP as well as SFP+
modules which requires a few more changes.  But not very many :)
Although some SFP modules seem to return something for the
comp_codes_10g read, which makes deciding which SFI mode to configure
non-trivial, short of providing an actual vendor/model switch.

Thanks,
Juli.