Bug#611595: grub-ieee1275: graphical display on openfirmware has poor color fidelity

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 31.01.2011 02:18, Daniel Kahn Gillmor wrote:
> Package: grub-ieee1275
> Version: 1.99~rc1-1
> Severity: minor
>
> Using grub-ieee1275 and the stock debian background for grub's
> graphical boot, i get a poor display of the colors of the image.
>
> the image being displayed is the stock debian squeeze grub background:
>
> 0 abc at tut:/tmp$ identify /usr/share/images/desktop-base/desktop-grub.png
> /usr/share/images/desktop-base/desktop-grub.png PNG 640x480 640x480+0+0 8-bit DirectClass 31.1KB 0.000u 0:00.019
> 0 abc at tut:/tmp$
>
> (also attached to this bug report).
>
> I've taken a photo of a powerpc machine with the monitor mis-rendering
> this image.  This misrendering seems to happen on all powerpc machines
> i've tried (both 32 and 64 bit, with ATI and NVIDIA GPUs).
All IEEE1275 I've seen around provide only indexed modes, one byte per 
pixel. So at most 256 colors. But only 16 are usable, since AFAIR 
set_palette on IEEE1275 doesn't work with colors >= 16. I may be wrong 
but attempting to change behaviour may result in worse bugs on machines 
which have the set_palette problem (e.g. having black on black text)

-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko