GNOME Shell will soon work without a 3D graphics driver
Source: https://fedoraproject.org/wiki/Features/Gnome_shell_software_rendering Adam Jackson, a Red Hat developer who works primarily on Fedora and x.org, has made changes to a number of components in the Fedora development tree that will allow the GNOME Shell, which makes use of graphic effects, to run on systems with graphics drivers which do not have 3D support. This should mean that under Fedora 17, scheduled for release next May, the control centre for the third GNOME generation is able to run on virtual machines or with VESA graphics drivers.
This has been achieved by using the llvmpipe driver, part of Mesa 3D, which tasks the main processor with performing calculations which the graphics driver normally assigns to the graphics processor. For 3D-intensive applications, such as games, this is too slow, even after distributing the workload across multiple threads and using CPU instruction set extensions such as SSE2. The GNOME Shell is, however, much more sparing in its use of graphic effects. On many computers and on systems virtualised using KVM, llvmpipe performance is adequate for the GNOME Shell to work smoothly – though Jackson has not yet optimised the various technologies involved (kernel, Mesa 3D, X.org, GNOME) for performance.
An as yet incomplete feature page for Fedora 17 provides some background information and details the aims of this approach. This feature could even replace fallback mode, with its echoes of GNOME 2, which GNOME 3 calls when the graphics driver does not provide the needed acceleration functions, though a decision on this is yet to be made. The concept should also work with other desktops which utilise acceleration features offered by recent graphics chips, though the Fedora development team does not expand on this point. Jackson does, however, make clear that the current code is likely to contain plenty of bugs.