Linux-kernel mailing list archive 2000-04,: RE: [linux-fbdev] Re: [DRIVER UPDATE] aty128fb - PPC

# RE: [linux-fbdev] Re: [DRIVER UPDATE] aty128fb - PPC

Geert Uytterhoeven (geert@linux-m68k.org)
Fri, 28 Jan 2000 10:44:21 +0100 (CET)

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On Thu, 27 Jan 2000, Brad Douglas wrote:
> > I don't completely agree. Putting them before or after is a matter of
> > style. The rare cases where this actually matters must usually be
> > hand-tuned. (For example, filling some HW cursor datas in the
> > framebuffer, so without using eieio, and then writing a register that
> > will cause the chip to use those datas. One eieio is needed before the
> > write in this case. I tend personally to prefer having them before.
>
> Do we know this for sure? I'm basing my code on what I've seen other people
> do. I don't have a PPC to test on (yet).
>
> > >Note that standard {read,write}[bwl]() are guaranteeing ordering
> > >themselves so when using those you should not need to add eieio()
> > >manually. (note this was not the case on the Alpha until some time
> > >during 2.3.x).
> >
> > Right.
>
> Hmm. I'm not at an optimization state right yet. Maybe I should just stick
> with read/write and ditch eieio()?

Yes, {read,write}[bwl]() are always safe. Optimizations can be cared about
later.

Gr{oetje,eeting}s,

    --
    Geert Uytterhoeven -- Linux/{m68k~Amiga,PPC~CHRP} -- geert@linux-m68k.org

    In personal conversations with technical people, I call myself a hacker. But
    when I'm talking to journalists I just say "programmer" or something like that.
    							    -- Linus Torvalds

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