The purpose of returning -EINVAL is to flush out the few people that
are using xorg.conf to change the location of their framebuffer. 
Changing the framebuffer location with xorg.conf on Linux is an
illegal operation that happened to work on older kernels but it is
very likely to break on newer ones. The problem is that xorg moved the
framebuffer without telling the kernel it has been moved, so where the
kernel thinks it is doesn't match where xorg put it. Letting it fail
through and make the new map will defeat one of the purposes of the
change.

On Wed, 8 Sep 2004 11:54:07 +0200, Felix K�hling <[EMAIL PROTECTED]> wrote:
> This would facilitate incremental driver development. For instance the
> Savage HwMC code uses a third framebuffer map. Since noone has made HwMC
> work yet, I wouldn't feel comfortable adding a permanent map for it yet.

Just don't add any permanent maps for HwMC until you figure out
everything that is needed.

> It may turn out to be useless in the end. The DDX should still have a
> chance to add the map, so this can be tried out first, before changing
> the kernel. Jon also mentioned the case where the offset isn't
> statically known but is somehow computed at runtime. I'm not sure if
> this is the case for HwMC, but allowing addmap to add new framebuffer
> maps in addition to permanent ones would make it possible.

If user space code is require to compute the map, that code should be
moved into the driver before making the permanent map change.

> Maybe one would have to add some extra sanity checks to make sure that
> new maps don't overlap with permanent maps.

End goal is to disallow any new maps for REGISTERS/FRAME_BUFFER.

Allowing maps into PCI space should be done in the driver. This is not
something that should be done from the X server since it requires
kernel coordination to do right.

> 
> Regards,
>   Felix
> 
> | Felix K�hling <[EMAIL PROTECTED]>                     http://fxk.de.vu |
> | PGP Fingerprint: 6A3C 9566 5B30 DDED 73C3  B152 151C 5CC1 D888 E595 |
> 



-- 
Jon Smirl
[EMAIL PROTECTED]


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