Messages in this thread | | | Date | Mon, 19 Jul 1999 07:15:56 -0600 (MDT) | From | Thomas Roell <> | Subject | Re: AGP & non-root mmap calls: "lending" priviledges to a client |
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In your message of 18 July 1999 you write:
> > 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
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