MCTP over PCI on AST2500

[Patrick Williams]

On Wed, Jan 15, 2020 at 09:51:38PM +0800, Jeremy Kerr wrote:
> 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.
> > 
> > https://github.com/openbmc/btbridge/blob/master/btbridged.c#L47
> > 
> > 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.
> 

Maybe by that time bus1 will be a mature replacement for dbus. ;)

Thanks for the reply.

-- 
Patrick Williams
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