On ppc64 systems that use the AST2500 graphics device, such as the Blackbird POWER9 system, the red and blue channels are inverted when the host is running in big endian mode. This is due to a ppc64 hardware quirk, which when combined with a hardware design fault in the AST2500 VGA controller results in a need to use software-based red-blue channel swapping.
Tested to fix color graphics on Debian sid/ppc64 on a Blackbird system. Timothy Pearson (2): PCI: Add CONFIG_PCI_ARCH_ENDIAN_AUTOSWAP drm/ast: Fix framebuffer color swapping on ppc64 systems arch/powerpc/Kconfig | 1 + drivers/gpu/drm/ast/ast_mode.c | 33 +++++++++++++++++++++++++++++++-- drivers/pci/Kconfig | 4 ++++ 3 files changed, 36 insertions(+), 2 deletions(-) -- 2.51.0
