PCI-Express support

[M. Warner Losh]

[[ replying to different aspects of this in different threads ]]

In message: <410D2FEA.5050504 at samsco.org>
            Scott Long <scottl at samsco.org> writes:
: Adding this for 5.3 is feasible, I think, and doesn't add a whole lot
: of risk.  PCI-E provides a legacy mde for interrupts that simulates
: PCI interrupt lines, so drivers can choose whether to use MSI or the
: legacy interrupt methods.

Code freeze is in 2 weeks.  I don't think it reasonable to have things
cooked enough by then to add this.  We've got enough going into 5.3
already, and these changes will be at the heart of the pci system,
which is a very big risk if it is done slightly badly.  Given the
large number of systems out there, I'd imagine that we'll have lots of
problems with this.  Smaller risk changes that Matt Dodd and I have
made over the years have resulted in big trouble.

I'd recommend that we give it a pass for 5.3.

Warner