MCTP over PCI on AST2500

Jeremy Kerr jk at
Thu Jan 16 00:51:38 AEDT 2020

Hi Patrick,

> > Just a suggestion - you probably don't want to be passing MCTP
> > messages over dbus - this is something we learnt from the IPMI
> > implementation.
> Is there a pointer to this "lesson learned" or the issues surrounding
> it?  It seems like the btbridge is still using dbus, so I assume
> host-ipmid is as well.
> I'm curious to understand what the issues were/are.

No, nothing that anyone had specifically documented. I recall there
were concerns with shuffling larger amounts of data over dbus,
particularly for things like firmware update over IPMI. Because we're
using a dbus signal for incoming messages, we could potentially be
writing a lot of data to multiple processes - and more than necessary
if those processes haven't set up their dbus matches correctly.

I don't think there's enough concern to change existing code over for,
more just a consideration for future designs, of which this is one.



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