How to know that a refresh is required ?

How to know that a refresh is required ?

[fuhz]

Hi !

I am currently writing a FrameBuffer driver for a custom embedded board.
I already read some documentation, including skeletonfb.c and vfb.c.

There are still some details that I don't really understand.

My board has a LCD controller which has its own internal buffer.
I am using DMA transfer to modify this buffer when I need to update the screen.

Programs using the framebuffer drivers (ie. gui apis) can write anytime to the
framebuffer internal buffer trough nmap.

My question : how do I know when to refresh my screen ?


Currently, I am thinking about these solutions :
- endless DMA transfer : the screen is always refresh (consumes power)
- timer based solution : refresh the screen every n milliseconds (latency)

I am waiting for your advices ! Are there other solutions ?

Thanks for all.


Best regards.

fuhz


PS:
I need to run GTK on an embedded board. So I guess writing a FrameBuffer driver
is not a bad choice.

Re: How to know that a refresh is required ?

[Jaya Kumar]

On Tue, Mar 9, 2010 at 5:50 PM,  <fuhz@free.fr> wrote:
> My board has a LCD controller which has its own internal buffer.

Cool.

> I need to run GTK on an embedded board. So I guess writing a FrameBuffer driver
> is not a bad choice.

Out of curiosity, which LCD controller is it and which embedded board
are you using? There should normally already be a driver for it in
Linux.

Best regards,
jaya