geode sc1200 2D graphics acceleration

geode sc1200 2D graphics acceleration

[Carlos Ojea Castro]

Hello!

I am drawing some graphics (a group of lines) using DirectFb in a
geode sc1200 (kernel 2.4).
I discovered that when I disable 2D hardware acceleration (by changing
'/root/.directfbrc' and '/etc/directfbrc') it is FASTER than drawing
with 2D hardware acceleration enabled.

Can't figure why. Any ideas?

Re: geode sc1200 2D graphics acceleration

[Lennart Sorensen]

On Thu, May 11, 2006 at 03:26:14PM +0200, Carlos Ojea Castro wrote:
> I am drawing some graphics (a group of lines) using DirectFb in a
> geode sc1200 (kernel 2.4).
> I discovered that when I disable 2D hardware acceleration (by changing
> '/root/.directfbrc' and '/etc/directfbrc') it is FASTER than drawing
> with 2D hardware acceleration enabled.
> 
> Can't figure why. Any ideas?

Could it be related to the video on the sc1200 being emulated by SMI (at
least as far as I understand things)?  Perhaps the acceleration simply
makes the BIOS/SMI stuff go do all the work, while with no acceleration,
the kernel writes all the bits directly, which is more efficient than
the BIOS/SMI emulation?  I think that is how the VSA stuff works on
those systems at least.  I have VGA disabled on the boards I use here,
so all I know is that the video is very slow on these systems when I
tried it once, and since I don't have a use for it, I disabled it.

Len Sorensen