Big-Endian problem with Fujitsu CoralPA

[Ian Romanick]

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Clemens Koller wrote:
> Eduard Fuchs schrieb:
>  > A few words about my system: This is a custom-designed board, based on a
>  > PowerPC CPU (MPC7448) and Marvell MV64560 chip-set. On the PCI bus are
>  > connnected graphic chip Fujitsu CoralPA(MB86296) and sATA Controller.
>  > The OS is Linux with kernel ver. 2.6.12.
>  >
>  > Now the problem – it is an Endian problem. The graphic chip supprts only
>  > up to 16-Bits color mode and Little Endian bits arrangement. This causes
>  > a wrong color picture on the screen. There is no possibility (anyway, I
>  > was not found) to correct the bits seqence direct in the graphics
>  > controller. I can activate bits-swapping on PCI controller (Marvell
>  > chip-set supports 32, resp. 64 bit-swapping). Then the colors are OK,
>  > but now I have errors in the picture representation.
> 
> Oh, sh***... you seem to have the same problem as we had with
> the Silicon Motion SM501 graphics chip on PowerPC's PCI (which is
> quite solved now...)

And the same problem I'm having on XGI XP10.

>  > Is this a possibility to adapt the X-server resp. Xlib so, that the
>  > pixel-data is from the CPU corrected? As a graphics driver I use
>  > framebufer device driver from the Linux kernel.
> 
> I don't know the CoralPA driver infrastructure of the kernel.
> 
> The xorg driver, however, could be fixed in the driver source.
> There is no need to modify the Xlib etc, AFAICT.
> The SM501 the xorg driver was modified for PPC architecture and is
> working now (for me). Just for your reference, see the last commits
> of the xf86-video-smi501 git tree at:
> git://people.freedesktop.org/~agd5f/xf86-video-smi501

The xf86SetWeight fix is technically correct.  However, it will cause
*every* application that uses Render to SEGFAULT.  I tried that with the
XP10 driver, and it prevented gnome from being happy.  I don't fully
understand the details of the problem, but keithp and benh do.  *shrug*

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