R600 and newer ATI cards need to load extra firmware for the free radeon driver to work correctly: http://www.x.org/wiki/radeonBuildHowTo#Missingfirmware

generate-config.pl complains when I add the required config to extraConfig:

  EXTRA_FIRMWARE radeon/R600_rlc.bin
  EXTRA_FIRMWARE_DIR /firmware/kernel

 GOT: # configuration written to .config
 GOT: #
 option not set correctly: EXTRA_FIRMWARE "radeon/R600_rlc.bin" radeon/R600_rlc.bin
 builder for `/nix/store/fnyabiypgy376gwps844ca776zmd0z39-linux-2.6.38_airlied.drv' failed with exit code 255
 cannot build derivation `/nix/store/xa30h4n3b05p4jfi51qniay8irqfjdqh-system.drv': 1 dependencies couldn't be built
 error: build of `/nix/store/xa30h4n3b05p4jfi51qniay8irqfjdqh-system.drv' failed

If I understand correctly this means that it fails because “radeon/R600_rlc.bin” doesn’t match radeon/R600_rlc.bin.

When I comment out this section of generate-config.pl the kernel compiles and accepts this configuration correctly:

$ zcat /proc/config.gz | grep EXTRA_FIR 
CONFIG_EXTRA_FIRMWARE="radeon/R600_rlc.bin"
CONFIG_EXTRA_FIRMWARE_DIR="/firmware/kernel"

Submitted by Cillian de Róiste on 2 April 2011 at 19:00