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[directfb-dev] Re: Non-working AGP hack
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[directfb-dev] Re: Non-working AGP hack

Quoting Ville Syrj?l? (
> I tried to glue some AGP stuff to DirectFB and G400 (patch included). So
> far all it manages to do is hang my system. I'm still able to use the
> magic sysrq key to reboot with my disks clean. It's supposed to put all
> video surfaces into AGP memory.

Cool, this is what I always dreamed of but didn't try out yet.
With AGP we could drop the system memory buffers completely and
create surfaces directly in the AGP aperture. We could save swapping
between system/video memory or do DMA transfers from AGP to video memory
and vice versa if there's a need for higher speed. Is the aperture resizable?

> I haven't found any decent docs on the agpgart interface so I'm not sure
> if what I'm doing is correct. Currently I allocate 64MB of AGP memory but
> I adjust the heap offset to 32MB so only the upper half of that gets used.
> This way I can check if the buffer is in card memory or AGP memory. Card <
> 32MB, AGP >= 32MB. 

With the introduction of memory pools (currently hardcoded to system and video)
this hack shouldn't be needed, I just hope that the code and data structures for
such management are still efficient enough for the old video/system model.
DirectFB should stay scalable, from embedded to high end ;)

> I tried running df_dok and from what I can tell it tried to do a
> StretchBlit or Blit3D from AGP memory to card memory. Maybe it's the
> cursor? All I see is the blue background.
> I'm too tired to mess with this now. Anyone want to point out what I'm
> doing wrong?

I think there were some AGP registers to be initialized, did you try it with
drm enabled?

I will apply the patch now and do some debugging and testing.

Best regards,
  Denis Oliver Kropp

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