Subject: Re: uiomove and bus-ified drivers
To: None <email@example.com>
From: maximum entropy <firstname.lastname@example.org>
Date: 12/18/1997 09:18:40
>From: Jason Thorpe <email@example.com>
>On Wed, 17 Dec 1997 22:58:45 +0100
> Leo Weppelman <firstname.lastname@example.org> wrote:
> > I was more or less hoping I missed something. That extra copy bothers
> > me.
>Um, bus_space_map() with the "linear" flag should make this work OK. Also,
>if you make this a machine-dependent driver, we can get by until
>bus_space_mmap() is implemented.
Yes, the code maps the framebuffer memory
BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_CACHEABLE, and the uiomove() does
in fact do the right thing. What's broken about it (and what I think
Leo is complaining about) isn't that it doesn't work, but rather that
the driver needs to know too much about the MD meanings of the
bus_space types, which should be opaque.
I'd like to hear more about bus_space_mmap(), it sounds like that
might be what we're looking for.
>Why use read/write? mmap is your friend!
Because it's there, mostly. The driver does have an mmap entry point
entropy -- it's not just a good idea, it's the second law.