Re: Screen regen buffer at 0x00b8000

[Richard B. Johnson]

On Fri, 20 May 2005, Jan-Benedict Glaw wrote:

> On Fri, 2005-05-20 09:48:35 -0400, Richard B. Johnson <linux-os@xxxxxxxxxxxx> wrote:
> >     len = getpagesize();
> >     if((fd = open("/dev/mem", O_RDWR)) == FAIL)
> >         ERRORS("open");
> >     if((sp = mmap((void *)SCREEN, len, PROT, TYPE, fd, SCREEN))==MAP_FAILED)
> >         ERRORS("mmap");
>
> Maybe you'd better not fiddle with physical memory, but use the device
> abstraction that's ment to offer that interface? That is, use a
> framebuffer driver and open /dev/fb* .
>
> MfG, JBG

No room for any more drivers. This just writes to a small LCD on an
embedded controller. There should be no reason why I can't
write directly to the physical memory. Anything written to the
physical screen buffer will show up on the screen, as long
as page zero is selected.

I think that I've discovered a bug. I know that what I have written gets
to the screen buffer because I can read in back! This doesn't make
any sense.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.11.9 on an i686 machine (5537.79 BogoMips).
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