Re: [RFC] asm-generic/pci_iomap.h: make custom PCI BAR requirements explicit

From: Luis R. Rodriguez
Date: Mon Oct 05 2015 - 13:09:42 EST


On Sun, Oct 04, 2015 at 09:02:04PM +0200, Arnd Bergmann wrote:
> On Saturday 03 October 2015 01:53:46 Luis R. Rodriguez wrote:
> > >
> > > Hmm, my gut feeling tells me that your approach won't solve the problem
> > > in general. s390 PCI is just weird in many ways and it will occasionally
> > > suffer from problems like this (as do other aspects of the s390 architecture
> > > that are unlike the rest of the world).
> > >
> > > Maybe Martin and Heiko can comment on this, they may have a preference
> > > from the s390 point of view.
> >
> > Hrm, so S390 is quirky is really odd ways that no other architecture is or
> > is at least for now not expected to be ?
>
> Absolutely correct. It is the only architecture I'm aware of that tries to
> support PCI that does not use pointer dereferences for MMIO.

So its not worth it to have a formal semantic via Kconfig for this and are
happy with the status quo of having to find out through a bot compile test
any changes in this domain fails?

Luis
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