Misconfigured framebuffer

Im trying to use kdrive on a pxa development board, however the display
is garbled, i think due to the xserver incorrectly configuring the
framebuffer.


Before starting freedesktop's Xfbdev fbset reports

mode "240x320-81"
        # D: 7.143 MHz, H: 26.752 kHz, V: 81.067 Hz
        geometry 240 320 240 320 16
        timings 140000 1 1 8 1 25 1
        accel false
        rgba 5/11,6/5,5/0,0/0
endmode


If i start Xfbdev with no options, after closing fbset reports          
 

mode "240x320-385"
        # D: 75.002 MHz, H: 137.871 kHz, V: 385.115 Hz
        geometry 240 320 1024 768 16
        timings 13333 144 24 29 3 136 6
        accel false
        rgba 5/11,6/5,5/0,0/0
endmode

Its set the virtual resolution to 1024x768, and modified the pixclocks
as well.


I see a similar problem was reported in January (1), the way that was
solved was to put the timing values in hw/kdrive/src/kmode.c.

It doesnt seem like a good long term solution to hard code configuration
data, shouldnt reasonable default values be obtainable via the
framebuffer ?

I suspect there is bug related to setting the virtual screen size that
caused this problem.


If i specify the correct geometry of my screen (its a portrait mode
screen) with.

# Xfbdev -screen 240x320x16

fbset reports thats its virtual screen size has been set to 800x600x16

mode "240x320-328"
        # D: 56.252 MHz, H: 115.271 kHz, V: 328.409 Hz
        geometry 240 320 800 600 16
        timings 17777 152 32 27 1 64 3
        accel false
        rgba 5/11,6/5,5/0,0/0
endmode


If i specify landscape mode, 320x240x16, the screen is clear and
readable, however the top portion of the screen is repeated at the
bottom, which always happens when you mix up portrait and landscape.

# Xfbdev -screen 320x240x16

mode "240x240-235"
        # D: 16.256 MHz, H: 59.765 kHz, V: 235.297 Hz
        geometry 240 240 320 240 16
        timings 61515 12 17 11 1 3 2
        accel false
        rgba 5/11,6/5,5/0,0/0
endmode


Xfbdev from Xfree86 4.3 works without any arguments and doesnt modify
the framebuffer settings at all.

I thought i had freedesktop's Xfbdev working at one stage in January,
however i cant get it back or workout what changed.

I did set pixclock and friends myself in the kernel, so maybe ive
misconfigured something, but it doesnt seem to be causing any problems
elsewhere.


Any ideas on whats going on ?


Thanks

Glenn


1) http://pdx.freedesktop.org/pipermail/xserver/2004-January/000701.html