Messy screen with ATI Mach64 on UltraIIi

[Hernest <mantra@elitel.biz>]

Hi,

I am trying to upgrade an UltraIIi from an old Aurora Linux (kernel 2.4.20)
to Debian Etch (2.6.18), but I cannot get a workable framebuffer using the
PCI video card on the system (an ATI Mach64 GT, see logs below).

I am booting with the Debian netinst CD, but at all resolutions I tried,
I always get a black verical stripe in the middle of the screen and sometimes
the right half of the screen remains black. The thing is barely usable as I 
cannot see most of the comman line. With 2.4.20 everything is OK.

If I disable the framebuffer (with video=atyfb:off fb boot option) the screen 
does not get messy, but the Debian menu is unusable, so I have to find a way
to make the fb to work.

I have not overwritten anything so far, so I could compare the video timings
under 2.4.20 (when the screen is OK) and under 2.6.18 (when I get the mess).
Incredibly they are exactly the same.

Any idea to have a decent fb like it used to be in 2.4.20?

Thanks

Hernest

== lspci
80:03.0 VGA compatible controller: ATI Technologies Inc 3D Rage IIC 215IIC 
[Mach64 GT IIC] (rev 3a) (prog-if 00 [VGA])

== fbset -i (on both distributions!!)
mode "1024x768-59"
    # D: 64.201 MHz, H: 47.769 kHz, V: 59.414 Hz
    geometry 1024 768 1024 4064 8
    timings 15576 128 56 27 3 136 6
    hsync high
    vsync high
    csync high
    accel true
    rgba 8/0,8/0,8/0,0/0
endmode

Frame buffer device information:
    Name        : ATY Mach64
    Address     : 0x1800000
    Size        : 4186112
    Type        : PACKED PIXELS
    Visual      : PSEUDOCOLOR
    XPanStep    : 8
    YPanStep    : 1
    YWrapStep   : 0
    LineLength  : 1024
    MMIO Address: 0x17ff800
    MMIO Size   : 2048
    Accelerator : ATI Mach64GT

== Relevant kernel log (2.4.20)
PROMLIB: Sun IEEE Boot Prom 3.10.8 1999/03/17 12:34
Linux version 2.4.20-2.3sparc (root@fry.rdu.redhat.com) (gcc driver version 
egcs-2.91.66 19990314/Linux (egcs-1.1.2 release) executing gcc version egcs-
2.92.11) #1 Wed Jan 15 18:27:52 EST 2003
ARCH: SUN4U
[ ... ]
Kernel command line: root=/dev/sda2 ro
Console: colour dummy device 80x25
Calibrating delay loop... 665.19 BogoMIPS
Memory: 124176k available (1880k kernel code, 536k data, 152k init) 
[fffff80000000000,0000000007ec0000]
[ ... ]
atyfb: 3D RAGE IIC (PCI) [0x4756 rev 0x3a] 4M EDO, 14.31818 MHz XTAL, 230 MHz 
PLL, 83 Mhz MCLK
Console: switching to colour frame buffer device 128x48
fb0: ATY Mach64 frame buffer device on PCI
pty: 1024 Unix98 ptys configured
[ ... ]

== Relevant kernel log (2.6.18)
PROMLIB: Sun IEEE Boot Prom 'OBP 3.10.8 1999/03/17 12:34'
PROMLIB: Root node compatible: sun4u
Linux version 2.6.18-5-sparc64 (Debian 2.6.18.dfsg.1-13) (dannf@debian.org) 
(gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)) #1 Mon May 21 
21:52:13 UTC 2007
ARCH: SUN4U
[ ... ]
Kernel command line: debconf/priority=low
PID hash table entries: 512 (order: 9, 4096 bytes)
Console: colour dummy device 80x25
[ ... ]
atyfb: 3D RAGE IIC (Mach64 GV, PCI) [0x4756 rev 0x3a]
atyfb: 4M EDO, 14.31818 MHz XTAL, 230 MHz PLL, 83 Mhz MCLK, 83 MHz XCLK
Console: switching to colour frame buffer device 128x48
atyfb: fb0: ATY Mach64 frame buffer device on PCI