Now that the r300 gallium driver is becoming usable it would be nice to have the ability to choose between the classic and the gallium driver adding an option to the xorg.conf file. This way distributions can provide both drivers with a defined default and let users change to the other if they prefer, rather than having to rename radeong to r300. Ideally in mesa the r300 driver could be compiled as r300c_dri.so and the gallium driver as r300g_dri.so, and r300_dri.so could be a symlink pointing to the default one (this way the default could be changed inside mesa). In -ati the default should be r300 (mesa default), leaving the user to force to r300c or r300g.
IMHO xorg.conf would be both overkill and insufficient: the r300g binary should just be called what it is, namely r300_dri.so, and then the distro could choose the default via the installation path / symlinks / whatever, and the user could override it per application via $LIBGL_DRIVERS_PATH.
Agreed with Michel. The DRI name is picked by the DDX as a known, safe value, and that should not be configurable. Users need to opt in for this. If distros want to provide overriding functionality, they can use a technique like Gentoo's for switching between GLX stacks.
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