code duplication, and it also hands you the map pointer so you don't
need to re-find it.
- Remove the permanent maps flag. Instead, for register and framebuffer
maps, we always check whether there's already a map of that type and
offset around. Move the Radeon map initialization into presetup (first
open) so it happens again after every takedown.
- Remove the split cleanup of maps between driver takedown (last close) and
cleanup (module unload). Instead, always tear down maps on takedown,
and drivers can recreate them on first open.
- Make MGA always use addmap, instead of allocating consistent memory in
the PCI case and then faking up a map for it, which accomplished nearly
the same thing, in a different order. Note that the maps are exposed to
the user again: we may want to expose a flag to avoid this, but it's
not a security concern, and saves us a lot of code.
- Remove rmmaps in the MGA driver. Since the function is only called during
takedown anyway, we can let them die a natural death.
- Make removal of maps happen in one function, which is called by both
drm_takedown and drm_rmmap_ioctl.
Reviewed by: idr (previous revision) Tested on: mga (old/new/pci dma),
radeon, savage
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* For the very latest on DRI development, please see: *
* http://dri.sourceforge.net/ *
************************************************************
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://precisioninsight.com/piinsights.html
For specific information about kernel-level support, see:
The Direct Rendering Manager, Kernel Support for the Direct Rendering
Infrastructure
http://precisioninsight.com/dr/drm.html
Hardware Locking for the Direct Rendering Infrastructure
http://precisioninsight.com/dr/locking.html
A Security Analysis of the Direct Rendering Infrastructure
http://precisioninsight.com/dr/security.html
************************************************************
* For the very latest on DRI development, please see: *
* http://dri.sourceforge.net/ *
************************************************************