Re: Color support for wsfb/Amiga

[David Brownlee <abs%absd.org@localhost>]

On Thu, 23 Jun 2022 at 07:05, Rin Okuyama <rokuyama.rk%gmail.com@localhost> wrote:
>
> (CC added to port-luna68k)
>
> On 2022/06/23 1:26, Jukka Andberg wrote:
> > The wsfb driver has been working only in monochrome with Amiga
> > native graphics mode due to the driver not supporting the Amiga's
> > planar video memory format.
> >
> > But actually I found out that there is a c2p routine [1] included
> > with xorg-server that works with shadowfb to convert the pixels into Amiga
> > planar format. Enabling it for 8-bit depth looks pretty simple. In
> > practice with this we could get 256 color mode on AGA chipsets.
> >
> > For other depths I didn't have much success so it is still
> > monochrome for non-AGA. Performance is also not that great, but it
> > is somewhat usable.
> >
> > Patch attached. Any thoughts before I commit?

Nice find! :)

> > [1] http://cvsweb.netbsd.org/bsdweb.cgi/xsrc/external/mit/xorg-server/dist/miext/shadow/shafb8.c
> >
> > P.S. With these wsfb changes the fake 1 bit depth hack can be removed
> > from kernel side.

Is it reasonable to leave it in as a compat for older X servers?

> Excellent! It works just fine on my A1200:
>
> https://twitter.com/LabDrunker/status/1539847364730822656
>
> It would be great if we can support color X server on luna68k, which
> also has "planer" framebuffer.
>
> A minor concern: With your patch, WSDISPLAYIO_GTYPE ioctl becomes
> mandatory even if the driver supports WSDISPLAYIO_GET_FBINFO. But,
> we can probably find broken drivers during beta test for netbsd-10,
> if such a driver is actually present/used ;)

I'm almost certain that every driver that supports
WSDISPLAYIO_GET_FBINFO also supports WSDISPLAYIO_GTYPE - I had a pass
through last Christmas when I was poking at the TURBOchannel X server
for pmax/alpha/vax.

It might be worth using another  wsdisplayio_fbinfo.fbi_flags bit
https://nxr.netbsd.org/xref/src/sys/dev/wscons/wsconsio.h#681
to represent planarAfb, rather than checking WSDISPLAY_TYPE_AMIGACC
(but even it it was, that doesn't block this commit in any way).

Actually it would have been nice if wsdisplayio_fbinfo had wstype, but
it's probably not worth versioning it for that alone :)

David