From: Cheshire Cat Fish <cat_fish@ho...> - 2003-05-14 21:38:03
A precariously balanced mixture of myopic optimism and rampant paranoia.
>I am developing a framebuffer driver for my PLC 69030 video card.
>I have gone through the Source code of the Sample framebuffer driver and i
>have some clarifications needed. Please clarify my doubts.
I am in the process of doing exactly this for a custom board. So this will
be like the blind leading the blind I suspect, but for what it is worth,
here is what I know...
>1.How does the Frame buffer driver Switches graphics modes, i mean how does
>it initializes the graphics system say in 640*480*256 mode and switch to
>say 800*600*24 mode.
>Does it depend on VESA BIOS calls to do this ?
I think this is up to you how you want to do this. In mine, I do it by
directly programming the hardware (no BIOS calls whatsoever). Basically,
you are told to set a mode - how you do that is up to you.
>2.How does the framebuffer driver achieve paging ?
>Say my display memoy is 4mb and i want divide it into 4 pages then how will
>i do this ?
I'm not sure what you mean by paging. Video memory isn't typically paged.
Is not all 4MB available at once?
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