Using VESA BIOS in Framebuffer driver

Hi Guys

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.

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 ?
Let me know.

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 ?

Please clarify my doubts

Thanks and regards
Seetaram
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Enterprise Linux Forum Conference & Expo, June 4-6, 2003, Santa Clara
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www.enterpriselinuxforum.com

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.

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.

Well that is very hardware dependent. Which kernel are you working with?

Does it depend on VESA BIOS calls to do this ?

NO!!! There does exist vesafb.c for this but this only works on a system 
with a BIOS. If you have a system with no BIOS you are out of luck.

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 ?

4 pages? 




-------------------------------------------------------
Enterprise Linux Forum Conference & Expo, June 4-6, 2003, Santa Clara
The only event dedicated to issues related to Linux enterprise solutions
www.enterpriselinuxforum.com