Re: [PATCH] framebuffer: fix screen corruption when copying

From: Mikulas Patocka
Date: Wed Sep 17 2014 - 07:44:32 EST




On Wed, 17 Sep 2014, Geert Uytterhoeven wrote:

> Hi Mikulas,
>
> On Tue, Sep 16, 2014 at 6:38 PM, Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
> > The patch also removes the references to fb_memmove in the code that is
> > commented out because fb_memmove was removed from framebuffer subsystem.
>
> I'd leave it as-is. Using plain memmove() is not correct, as it should operate
> on MMIO space, not RAM. On x86 it works with memmove(), though, but
> not on all architectures.
>
> Gr{oetje,eeting}s,
>
> Geert

That code is disabled with #if 0. So it doesn't matter if it's incorrect
in some specific situation.

The purpose of that disabled code is to be able to verify that the bug is
in bitcpy_rev. I get screen corruption - so I enable that "memmove"
statement - the screen corruption goes away - so I know that the bug is in
bitcpy_rev.

Mikulas
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