Re: Screen Refresh

[Lucas Correia Villa Real <lucasvr@gobolinux.org>]

On Wednesday 05 May 2004 11:02, Jan-Benedict Glaw wrote:
> On Wed, 2004-05-05 10:47:00 -0300, Lucas Correia Villa Real
> <lucasvr@gobolinux.org>
>
> wrote in message <200405051047.00127.lucasvr@gobolinux.org>:
> > I'm writing a device driver for a monochrome LCD display managed by a
> > controller that will be plugged into the CPU through a SPI, that is, I
> > cannot directly memory-map it's address, since the communication will be
> > done via a serial interface.
>
> So I see two ways.
>
> 	If you only want to be able to output text, then you'd register
> as a console device. You'll then get write accesses, which you can then
> promote to real hardware.
>
> 	If you really want to provide a graphical display, you'll need
> something like two buffers (one the kernel writes to, probably a 2nd one
> to store the "current" image to only send down the changed pixels).
> That'll come along with some timed function - not nice, but may work.
>
> In theory, you'd try to not actually provide a framebuffer (memory), but
> to simply give pointers to all those accelerated functions. If you've
> got enough luck, you'll only see these functions called, so that you can
> do graphics with merely no overhead of polling the whole memory...

Hmm, that's a good idea! I'll need to have graphical display, so I think I'll 
start by writing a first release using this double buffering technique, and 
later try to play with accelerated functions.

Thanks for the help!
Lucas


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