Revision as of 11:03, 20 January 2012

DRI2 Drivers Only

Summary

Ship only DRI2 3D drivers in Fedora 17

Owner

Name: Adam Jackson
Email: ajax@redhat.com

Current status

Targeted release: Fedora 17
Last updated: 2011-12-15
Percentage of completion: 90%

Feature is essentially complete. DRI1 drivers are no longer built, kernel support has been dropped, and various support packages like Glide have been retired. Remaining work items:

Disable DRI1 at build time in the X server
Disable building DRI1 support in 2D drivers
Set 2D driver defaults for llvmpipe performance

Detailed Description

Upstream Mesa has dropped all DRI1 driver support. To wit, the following 3D drivers are no more:

i810
mga
r128
savage
sis
tdfx
unichrome

As a practical matter, all of these drivers have been unmaintained for several years already. The hardware covered by these drivers corresponds to, at best, DirectX 7 and OpenGL 1.5, often with severe hardware limitations on rendering surface size and texturing functionality.

Since modern desktop environments place increasing demands on the 3D stack, it is desirable to cut off "native" acceleration support for older chipsets. Instead these chips will be supported by the llvmpipe driver in Mesa, which features robust OpenGL 2.x support and a high-performance JIT based on LLVM for the rendering pipeline.

Features/Gnome shell software rendering details additional work planned for F17 to enable the llvmpipe driver to perform adequately for devices without native DRI2 support. This will require additional X driver performance work, and consequently the above drivers will be among the first ones so modified.

To be clear, this removes only the DRI1 3D support for older chipsets. Native 2D drivers will still be provided for the affected hardware.

Benefit to Fedora

Users of older DRI1-only hardware will gain significant OpenGL functionality, and will be using a driver that can be tested (and fixed) on any machine without needing to search out old hardware, improving the support experience.

Libraries and applications developed on F17 and above can assume a baseline functionality of approximately OpenGLES 2.0.

Scope

Kernel

DRM drivers for affected hardware will be disabled.

Mesa

The mesa-dri-drivers-dri1 subpackage - not installed by default in F16 - will be dropped.

X11

The X server and DDX drivers will be built without DRI1 support.

Many drivers, including former DRI1-enabled drivers, will be modified for improved performance with llvmpipe.

How To Test

Compare runs of 'glxinfo' on affected hardware before and after. The OpenGL renderer string will change to that of llvmpipe. Functionality of llvmpipe should be essentially identical across all non-DRI2 hardware.

User Experience

Affected hardware may perform better or worse, depending on the specific application and CPU power.

Dependencies

None.

Contingency Plan