Re: Accelerated frame buffer functions

Haakon Riiser
2005-02-02T17:45:37Z

[Jon Smirl]

> On Wed, 2 Feb 2005 16:41:39 +0100, Haakon Riiser
> <haakon.riiser@fys.uio.no> wrote:
>> Thanks for the tip, I hadn't heard about it. I will take a look,
>> but only to see if it can show me the user space API of /dev/fb.
>> I don't need a general library that supports a bunch of different
>> graphics cards. I'm writing my own frame buffer driver for the
>> GX2 CPU, and I just want to know how to call the various functions
>> registered in struct fb_ops, so that I can test my code. I mean,
>> all those functions registered in fb_ops must be accessible
>> somehow; if they weren't, what purpose would they serve?
>
> You should look at writing a DRM driver. DRM implements the kernel
> interface to get 3D hardware running. It is a fully accelerated driver
> interface. They are located in drivers/char/drm

Have the standard frame buffer drivers been abandoned, even
for devices that have no 3D acceleration (like the Geode GX2)?
I took a quick look at the DRM stuff, and it looked like extreme
overkill for what I need, if it even can be used for what I want
to do. At first glance it looked like this is only relevant for
OpenGL/X11 3D-stuff, which I have absolutely no use for.

GX2 is an integrated CPU/graphics chip for embedded systems.
We have third party applications that use the framebuffer device,
and I was hoping to make things faster by writing an accelerated
driver. The only thing I need answered is how to access fb_ops
from userspace. If that is impossible because all the framebuffer
code is leftover junk that no one uses anymore, or even /can/
use anymore because the userspace interface is gone, please let
me know now so I don't have to waste any more time.

--
Haakon