RE: [Dri-devel] Want to help enable DRI on multiple-head cfg's

[Andreakis, D. (MED) <Dea...@me...>]

Alex,

Thanks for the information. I will look thru the mergedfb patch code
asap. I think your idea of sharing one framebuffer as 2 virtual fb's
could work...thanks!

-dean andreakis

-----Original Message-----
From: Alex Deucher [mailto:ag...@ya...]
Sent: Thursday, June 26, 2003 3:27 PM
To: Andreakis, Dean (MED); dri...@li...
Subject: Re: [Dri-devel] Want to help enable DRI on multiple-head cfg's


I don't know what's involved in making the DRI work on multiple
physical graphics cards, but if you want HW accelerated 3D on a
dualheaded radeon card check out my mergedfb patch:

http://bugs.xfree86.org//cgi-bin/bugzilla/show_bug.cgi?id=276

I'm not sure you'll be able to get dual independant 3D accelerated
heads from a dualheaded card since there is only one 3D engine.  I
don't know if it could be made to work with things like different color
depths.  Then there is the issue of 2 heads fighting for the same
graphics engine.  there would have to be some sort of coordination. 
perhaps you could somehow make the second head a 3D client of the
first?  I could be wrong though; I'm still learning the 3D side of
things.

Actually htinking about it more, you could take the mergedfb code and
rearrange it a bit to give the impression of being two separate
independant heads, but actually sharing a framebuffer on the backend. 
just divide the big frambeuffer into two "virtual" framebuffers that
corresponded to each "independant" head.  I think both heads would have
to be the same color depth.

Alex

--- "Andreakis, Dean (MED)" <Dea...@me...> wrote:
> I would like to help enable DRI for multiple head configurations but
> I
> need a little direction to get started. I understand from previous
> postings and comments I have seen in the source that DRI is currently
> disabled in multiple head cfg's because of "sync. problems" but I am
> not
> sure of the exact technical meaning of this. 
> 
> My development platform is an iBook w/ an ATI Radeon Mobility 7500,
> Debian (sid)(2.4.19 kernel), XFree86 v4.3.0 and Michael Danzer's DRI
> trunk. I did some initial work on the 2D radeon driver to enable dual
> independent heads and this works ok for now. I then backed-off to
> just
> the internal panel and using Michael's DRI trunk got DRI enabled. Now
> I
> would like to take the last step and get DRI going w/ this dual
> independent head configuration. 
> 
> I am not sure what modules to start looking at for this effort...i.e.
> are the changes required in the XFree86 3D drivers in
> xc/lib/GL/mesa/src/drv/radeon/ and/or in the kernel-mode drm modules
> in
> xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel/. Also,
> some
> direction from a design standpoint and hints/tips on where to look
> would
> be useful.
> 
> -dean andreakis
> 


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