Subject: Re: maple_attach_dev
To: None <gillham@vaultron.com>
From: Marcus Comstedt <marcus@idonex.se>
List: port-dreamcast
Date: 03/17/2001 01:19:17
>>>>> "Andrew" == Andrew Gillham <gillham@vaultron.com> writes:

  Andrew> Are the 3 functions "sub functions" or "multi functions" on these
  Andrew> devices?  You could just create a Maple Multi Function (mmf) device
  Andrew> that attaches and all of the devices connect to it.

I'm not sure what you mean by the distinction "sub function" vs "multi
function".  A function is something the device can do.  It can have
just one function, or several functions.  Which functions are
implemented are marked with bits in a bitfield that is part of the
device information packet.  Theoretically, a device could implement
zero functions, by leaving the bitfield empty, but that would make it
a rather pointless device since it wouldn't be able to do anything.
The only maple commands that are not addressed to a specific function
is the "request device information" command, which you use to find out
what the device supports, and the reset/shutdown commands.


  Andrew> Something like:
  Andrew> mmf0 at maple0 port 0 subunit 1
  Andrew> kbd0 at mmf0
  Andrew> lcd0 at mmf0
  Andrew> mmf1 at maple0 port1 subunit 1
  Andrew> vmu0 at mmf1
  Andrew> kbd1 at mmf1
  Andrew> ...

Sure, but what's the point of the "mmf" device?  Wouldn't it be
simpler to just attach the kbd0 etc directly to maple0?


  Andrew> So you don't have an actual "vmu" attached, just the functions.  But
  Andrew> if there is a vmu device, plus 3 sub devices, that is a more difficult
  Andrew> problem. :-)

Well, isn't the "device + 3 sub devices" what you're suggesting with
the "mmf" device?


  // Marcus