Re: [Linux-fbdev-devel] [PATCH 1/2] fb: add support for foreign endianness

Clemens Koller
2008-02-18T23:35:35Z

Valdis.Kletnieks@vt.edu schrieb:
> On Mon, 18 Feb 2008 08:18:47 +0100, Krzysztof Helt said:
>> I know two fb drivers which use endianess information (pm2fb and s3c2410fb).
>> Both resolve endianess at driver level. Actually, both handle it by setting special
>> bits so the graphics chip itself reorder bytes to transform foreign endianess.
>> I understand that this patch is for chips which cannot reorder bytes by themselves.
>
> Does anybody know of such a chip that's actually available in the wild? Or are
> we writing drivers for speculative possible chips?
>

I had troubles with the Silicon Motion SM501/SM502 endianess on PowerPC PCI vs. LocalBus.
The chip also has a register to swap endianess, but that seems to only affect some
LocalBus modes.
The current fb and X drivers are working, but when it comes to font
aliasing and hw-acceleration, the problems start to rise again...

Regards,

Clemens