Re: Migrating ports from XFree86 to Xorg (Was: Changing default X11_TYPE from native to modular for some platforms)

[Frank Wille <frank%phoenix.owl.de@localhost>]

On Tue, 27 Sep 2011 10:23:41 -0400
Michael <macallan1888%gmail.com@localhost> wrote:

> You can switch to graphics on ioctl(WSDISPLAYIO_SMODE,
> WSDISPLAYIO_MAPPED) and back on WSDISPLAYIO_EMUL. Some drivers use it
> to switch the hardware to 24bit for X while running the console in 8
> bit.

Ahh! That was the missing piece for my puzzle. Thanks! :)

Does SMODE expect the mapped frame buffer mode to have the same resolution
as the console mode before?


> If you run something VGA-ish in text mode you may also
> want to think about implementing blitter support - Cirrus and S3 docs
> shouldn't be that hard to find.

We can think about that, but the speed for the current grf text consoles
is fine, and we can reuse the code for wsdisplay emulops (or vcons
rasops - I will definitely do vcons!).

All grf devices except one (grful) support a text mode, which only has to
move a character and attribute byte for each position. This is fast enough
with the CPU.


> You will want to implement at least
> an accelerated putchar() using whatever colour expansion scheme your
> hardware supports so you don't have to map the framebuffer at all

As I understand wsdisplay doesn't need to know about the frame buffer
in text console mode? It just calls putchar() and the driver does the
rest.


> [...] This can be
> enabled using the BUS_SPACE_MAP_PREFETCHABLE flag in bus_space_(m)map
> () if your underlying pmap supports it.

Bus space is a difficult topic for most 68k ports and especially for
amiga. ;)

Only a few drivers use bus_space at all, because they rely on common
MI driver code. The rest, like the grf drivers, doesn't.

I would love to see a common 68k bus space implementation some day...


-- 
Frank Wille