Re: [PATCH] video: fbdev: atyfb: only use ioremap_uc() on i386 and ia64

From: Andy Shevchenko
Date: Wed Nov 13 2019 - 04:32:04 EST


On Wed, Nov 13, 2019 at 08:38:15AM +0100, Arnd Bergmann wrote:
> On Wed, Nov 13, 2019 at 8:27 AM Christoph Hellwig <hch@xxxxxx> wrote:
> >
> > On Tue, Nov 12, 2019 at 10:24:23PM +0000, Luis Chamberlain wrote:
> > > I think this would be possible if we could flop ioremap_nocache() to UC
> > > instead of UC- on x86. Otherwise, I can't see how we can remove this by
> > > still not allowing direct MTRR calls.
> >
> > If everything goes well ioremap_nocache will be gone as of 5.5.
>
> As ioremap_nocache() just an alias for ioremap(), I suppose the idea would
> then be to make x86 ioremap be UC instead of UC-, again matching what the
> other architectures do already.

I think it's right thing to do, i.e. assume that ioremap() always does strong
UC independently on MTRR settings.

--
With Best Regards,
Andy Shevchenko