linear frame buffer address

[szhou42]

Hi, I am currently writing a simple vesa driver.

What's the typical address of a linear frame buffer?

I got LFB equal to 0xfc000000, and the call to vesa get mode function does return a 0x004f in AX register, which means the call succeed.

but is it typical for LFB to be such a high address? The qemu can only simulate a maximum of 2047 mb of memory, there is no way i can access a physical address 0xfc000000

Thanks!

[Sik]

The framebuffer is in video RAM, not normal RAM, so of course it will be located in a different address.

[szhou42]

The framebuffer is in video RAM, not normal RAM, so of course it will be located in a different address.

OHOHOH you remind me, those physical memory are mapped to video memory, thanks!

[shmx]

there is no way i can access a physical address 0xfc000000

And you try to x86 CPU can address up to 4 GB of physical memory (in 32-bit mode, no PAE, PSE). physical memory != RAM. Physical memory includes RAM, ROM, MMIO, VRAM etc.