Re: S3 Frame Buffer

Jeff Garzik (jgarzik@pobox.com)
Tue, 01 Jun 1999 08:55:59 -0400

Gerd Knorr wrote:
>
> > The kernel also needs {check,request,release}_mmio for MMIO regions,
> > just like {check,request,release} region, so that the vesafb driver
> > won't start writing to a framebuffer already mapped by a driver before
> > it.
>
> [ ... ]
>
> > It may be possible to have hardware acceleration in X, if vesafb
> > correctly specifies the MMIO region.
>
> vesafb doesn't know where the mmio regions are, it only knows where the
> framebuffer memory starts. You will not get accelerated X with vesafb.

Consider the recent S3-specific vesafb hacks. It shouldn't be too hard,
after you detect an S3 chip, to fill in the mmio_start/mmio_len fields
in struct fb_info with useful values. Once those values are filled in,
X should be able to accelerate the chip.

> And _mmio would'nt work either...

Would you mind elaborating on this? If I have a vesafb hacked to
support S3 and mmio as above, and a custom S3 driver, wouldn't
{check,request,release}_mmio, along with the existing
{check,request,release}_region, help make sure that those two drivers
don't collide?

Thanks,

Jeff

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