> > A question that has been presented to us is that of direct mmap() access to
> > AGP bridge-viewed RAM. For our AGP/GART device, the client non-root
> > processes that are coordinated by the X server are handed a "magic cookie"
> > that can be used to "bless" a device file descriptor (allowed inside the
> > kernel) ... and thus allow any mmap as needed directly from the AGP/GART
> > device. In general, then, only smart and X-server coordinated processes are
> > then able to do this, enhancing stability, but decreasing unneeded
> > centralization.
> >
> > Are there any plans to allow "handing over" priviledges to clients, from one
> > process to another? Should a technique of "trusted-cookies" be used to
>
> It already exists for general handle passing for file handles.
Can you give me a pointer to that meachansim, and also how it's
handled in other Unix like operating systems ?
> Precision Insight
> have a fairly clean working kernel module (free software) in progress for doing
> the direct render resource management 'right' in a similar style to SGI.
Their arppoach is very specific to their implementation of OpenGL. It
does not address AGP and other issues relevant to current graphics
boards (from the documentation I have seen). What we are trying to
make available is a relatively simple AGP driver that addresses the
limited area of AGP mapping and management without trying to cover
all the issues that are involved to do direct rendering.
- Thomas
-- Thomas Roell /\ An imperfect plan executed violently Xi Graphics / \/\ _ is far superior to a perfect plan. thomas@xig.com / / \ \ / Oelch! \ \ George Patton- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/