Re: UTF-8 on 8.0-CURRENT: Yes We Can!

From: Ed Schouten <ed_at_80386.nl>
Date: Tue, 14 Jul 2009 22:40:28 +0200
Hi Vladimir,

* Vladimir Grebenschikov <vova_at_fbsd.ru> wrote:
> In past graphical console draw text not too quick.
> I've tried to live with VESA mode of sc (to match high resolution of
> notebook display). But it was really slow.
> Probably, your driver will be much faster ?

Even though I like VESA, it's probably hard, if not impossible to get it
working, mainly because we need vm86 to reprogram the hardware, which is
not present on amd64. One of the things on my todo list is to figure out
how the Intel hardware works, so we have an accelerated driver on those
systems. This should also make it a lot more attractive to implement
things like kernel modesetting somewhere in the future.

Right now I'm using the VGA driver that Marcel Moolenaar wrote for
vtc(4) in 2005. I basically made two optimisations:

- Similar to syscons, I use a 25 Hz timer to refresh the modified
  portion of the screen, instead of handling input synchronously, like
  vtc(4) does. This timer will not be used during boot or while in the
  kernel debugger/experiencing a kernel panic. Writing data to the TTY
  will just store data in buffers, which means I can write data to the
  TTY at approximately 5 MB/sec on my 2.2 GHz MacBook.

- I made some optimisation to prevent unneeded reads/writes to the VGA
  hardware.

I have to say the speed is acceptable. Using my console driver in VMware
Fusion is still a bit slow, but not driving you insane. Because it can't
use the 25 Hz timer during boot, it takes some extra time to print the
startup messages there.

There is still room for improvement, so I suspect it won't be a problem
by the time I'm done.

-- 
 Ed Schouten <ed_at_80386.nl>
 WWW: http://80386.nl/

Received on Tue Jul 14 2009 - 18:40:29 UTC

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