[Xorg] Getting GATOS branch created on Xorg

Vladimir Dergachev volodya at mindspring.com
Fri Aug 20 09:47:27 PDT 2004

On Fri, 20 Aug 2004, Jon Smirl wrote:

> There is already code in X for coordinating video memory usage with
> DRM. The DRM memory manager keeps 2D X from stomping on 3D buffers.
> Same mechansim can be used to protect the video streaming memory.

Last time I checked this was not straightforward. Furthermore, aren't 
3d buffers fixed in size after Xserver startup ?

> Several other cards use kernel based v4l drivers, why is the radeon
> special?

I am only aware of bt848 cards - these are standalone video capture device 
and do not have to share anything.

Also, AIW cards do have a v4l interface - however it is an auxiliary 
driver only, it needs Xv program to setup the video stream for any data to 
be available (this way it can use video memory already allocated by 
Xserver for video stream)


                       Vladimir Dergachev

> --- Vladimir Dergachev <volodya at mindspring.com> wrote:
>> On Thu, 19 Aug 2004, Jon Smirl wrote:
>>> Why not add v4l support to the DRM device driver and ignore the X
>>> driver?
>> Because you would not be able to run X then. You do not want your
>> offscreen pixmaps overwritten with video data on a random basis.
>> The only way this can work is if the video memory allocator is
>> accessible
>> from video-in code.
> =====
> Jon Smirl
> jonsmirl at yahoo.com
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