Created attachment 134111 [details]
kernel config

I got a Radeon 9600 Pro (rv350, Mac Version, AGP) card for my PowerMac G5 7,3. I get a nice display, but in all funky colours, even at the console level without X. X too has the colour issue with radeon or fbdev.

Console output shows red instead of green, green instead of blue, blue instead of red. The dark grey is still grey, but a bit brighter. Same sympthoms on kernel 4.13.0 and 4.12.10.

System:
# inxi -b
System:    Host: T800 Kernel: 4.13.0-gentoo ppc64 bits: 32 Console: tty 0 Distro: Gentoo Base System release 2.3
Machine:   No /sys/class/dmi; using dmidecode: dmidecode is not installed.
CPU:       Dual core PPC970FX altivec supported (-MCP-) speed/max: 2300.000000MHz/2300 MHz
Graphics:  Card: Advanced Micro Devices [AMD/ATI] RV350 [Radeon 9550/9600/X1050 Series]
           Display Server: X.org 1.19.3 drivers: ati,radeon (unloaded: modesetting,fbdev)
           tty size: 211x55 Advanced Data: N/A for root out of X
Network:   Card: Apple K2 GMAC (Sun GEM) driver: gem
Drives:    HDD Total Size: 500.1GB (4.4% used)
Info:      Processes: 84 Uptime: 2:23 Memory: 3133.4/7858.0MB Init: systemd Client: Shell (bash) inxi: 2.3.36

Card:
0000:f0:10.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV350 [Radeon 9550/9600/X1050 Series] (prog-if 00 [VGA controller])
	Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] R9600 Pro primary (Asus OEM for HP)
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 16 (2000ns min), Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 48
	Region 0: Memory at a0000000 (32-bit, prefetchable) [size=256M]
	Region 1: I/O ports at 0400 [size=256]
	Region 2: Memory at 90000000 (32-bit, non-prefetchable) [size=64K]
	Expansion ROM at 90020000 [disabled] [size=128K]
	Capabilities: [58] AGP version 2.0
		Status: RQ=80 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- HTrans- 64bit- FW+ AGP3- Rate=x1,x2,x4
		Command: RQ=32 ArqSz=0 Cal=0 SBA+ AGP+ GART64- 64bit- FW- Rate=x4
	Capabilities: [50] Power Management version 2
		Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
	Kernel driver in use: radeon
	Kernel modules: radeon