Adding new media types to if_media.h
Mike Karels
mike at karels.net
Thu Feb 26 14:21:49 UTC 2015
> I'm doing some work for Mellanox and we need some 100GBase types for
> coming hardware products too.
> I think we are not using the 32-bits of "ifm_media" well enough.
> Has it been discussed to add more bits to "IFM_NMASK" and have more
> ethernet types like IFM_ETHER_0, IFM_ETHER_1, IFM_ETHER_2, IFM_ETHER_3 ....
> Currently 5 IFM types are defined. If 2 more bits can be added to
> IFM_NMASK we have 5 bits total giving us 2**5 = 32 IFM types. Then it
> should be possible to define "(32 - 5) * 32 = 864" more ethernet types,
> which I think should be enough for now - or we add even one more bit to
> IFM_NMASK ?
Did you have specific bits in mind? I'm fairly sure they are all assigned
to something now. The adjacent bits are used for the subtype/variant and
options. Most of the options are used, maybe not all.
I haven't checked whether the "instance" field is still used, though. It
was for MII PHY numbers, I believe.
If we had more bits, it seems better to put them directly into the subtype
field rather than the type field.
Mike
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