RE: [PATCH]: Prevent sn2 ptc code from executing on all ia64 subarches

["Luck, Tony" <tony.luck@intel.com>]

> I think this is too complicated.  Initcall ordering is fragile as it
> is. 
...

> Can you use the existing machine vector infrastructure to solve this
> problem?  For example, what if you added a "platform_device_setup()"
> hook that is a no-op on most platforms, but maps to sn_device_setup()
> in the SN2 machine vector?  platform_device_setup() would itself be
> called as a device_initcall().

This solution would move all the sn2 initializaions into the
device_initcall sequence.  Which might cause some ordering
problems.  E.g. sn_pci_init() is a "subsys_initcall" ... and I
expect that it really needs to happen before any of the
device_initcalls.

So there would have to be a sn_* version for potentially each of
the 7 existing levels of initcall to keep the ordering.

-Tony