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Thomas Hellstrom
ba4e7d973d
TTM is a GPU memory manager subsystem designed for use with GPU devices with various memory types (On-card VRAM, AGP, PCI apertures etc.). It's essentially a helper library that assists the DRM driver in creating and managing persistent buffer objects. TTM manages placement of data and CPU map setup and teardown on data movement. It can also optionally manage synchronization of data on a per-buffer-object level. TTM takes care to provide an always valid virtual user-space address to a buffer object which makes user-space sub-allocation of big buffer objects feasible. TTM uses a fine-grained per buffer-object locking scheme, taking care to release all relevant locks when waiting for the GPU. Although this implies some locking overhead, it's probably a big win for devices with multiple command submission mechanisms, since the lock contention will be minimal. TTM can be used with whatever user-space interface the driver chooses, including GEM. It's used by the upcoming Radeon KMS DRM driver and is also the GPU memory management core of various new experimental DRM drivers. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Jerome Glisse <jglisse@redhat.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
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* For the very latest on DRI development, please see: *
* http://dri.freedesktop.org/ *
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The Direct Rendering Manager (drm) is a device-independent kernel-level
device driver that provides support for the XFree86 Direct Rendering
Infrastructure (DRI).
The DRM supports the Direct Rendering Infrastructure (DRI) in four major
ways:
1. The DRM provides synchronized access to the graphics hardware via
the use of an optimized two-tiered lock.
2. The DRM enforces the DRI security policy for access to the graphics
hardware by only allowing authenticated X11 clients access to
restricted regions of memory.
3. The DRM provides a generic DMA engine, complete with multiple
queues and the ability to detect the need for an OpenGL context
switch.
4. The DRM is extensible via the use of small device-specific modules
that rely extensively on the API exported by the DRM module.
Documentation on the DRI is available from:
http://dri.freedesktop.org/wiki/Documentation
http://sourceforge.net/project/showfiles.php?group_id=387
http://dri.sourceforge.net/doc/
For specific information about kernel-level support, see:
The Direct Rendering Manager, Kernel Support for the Direct Rendering
Infrastructure
http://dri.sourceforge.net/doc/drm_low_level.html
Hardware Locking for the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/hardware_locking_low_level.html
A Security Analysis of the Direct Rendering Infrastructure
http://dri.sourceforge.net/doc/security_low_level.html