[PATCH 2/2] drm/tiny: Add ofdrm for Open Firmware framebuffers

[Thomas Zimmermann]

Hi

Am 21.05.22 um 04:49 schrieb Benjamin Herrenschmidt:
> On Thu, 2022-05-19 at 09:27 +0200, Thomas Zimmermann wrote:
> 
>> to build without PCI to see what happens.
> 
> If you bring any of the "heuristic" and palette support code in, you
> need PCI. I don't see any reason to take it out.
> 
>> Those old Macs use BootX, right? BootX is not supported ATM, as I don't
>> have the HW to test. Is there an emulator for it?
> 
> It isn't ? When did it break ? :-)

I meant that BootX is not (yet) supported by this new driver. The Linux 
kernel overall probably supports it.


> 
>> If anyone what's to make patches for BootX, I'd be happy to add them.
>> The offb driver also supports a number of special cases for palette
>> handling. That might be necessary for ofdrm as well.
> 
> The palette handling is useful when using a real Open Firmware
> implementation which tends to boot in 8-bit mode, so without palette
> things will look ... bad.
> 
> It's not necessary when using 16/32 bpp framebuffers which is typically
> ... what BootX provides :-)

Maybe the odd color formats can be tested via qemu.

I don't mind adding DRM support for BootX displays, but getting the 
necessary test HW with a suitable Linux seems to be laborious. Would a 
G4 Powerbook work?

Best regard
Thomas

> 
> Cheers,
> Ben.
> 
>> Best regards
>> Thomas
>>
>>> Gr{oetje,eeting}s,
>>>
>>>                           Geert
>>>
>>> --
>>> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
>>>
>>> In personal conversations with technical people, I call myself a hacker. But
>>> when I'm talking to journalists I just say "programmer" or something like that.
>>>                                   -- Linus Torvalds
>>
>> -- 
>> Thomas Zimmermann
>> Graphics Driver Developer
>> SUSE Software Solutions Germany GmbH
>> Maxfeldstr. 5, 90409 Nürnberg, Germany
>> (HRB 36809, AG Nürnberg)
>> Geschäftsführer: Ivo Totev
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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