Files
linux/drivers/gpu/drm
Ben Widawsky c7c48dfdff drm/i915: Add VM to context
Pretty straightforward so far except for the bit about the refcounting.
The PPGTT will potentially be shared amongst multiple contexts. Because
contexts themselves have a refcounted lifecycle, the easiest way to
manage this will be to refcount the PPGTT. To acheive this, we piggy
back off of the existing context refcount, and will increment and
decrement the PPGTT refcount with context creation, and destruction.

To put it more clearly, if context A, and context B both use PPGTT 0, we
can't free the PPGTT until both A, and B are destroyed.

Note that because the PPGTT is permanently pinned (for now), it really
just matters for the PPGTT destruction, as opposed to making space under
memory pressure.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-12-18 15:31:20 +01:00
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2013-10-09 15:55:33 +10:00
2013-12-18 15:31:20 +01:00
2013-10-09 15:55:33 +10:00
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************************************************************
* For the very latest on DRI development, please see:      *
*     http://dri.freedesktop.org/                          *
************************************************************

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