Re: Screen Refresh

[Jan-Benedict Glaw <jbglaw@lug-owl.de>]

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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...

MfG, JBG

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