[SeaBIOS] how sea bios set VGA bar address?

Gerd Hoffmann kraxel at redhat.com
Mon Nov 10 11:00:43 CET 2014


  Hi,

> so i wonder where in source code of seabios calculate PCI BAR address?

src/fw/pciinit.c initializes all pci devices and assigns addresses to
the bars.  bars are sorted by size for best packing, so the addresses
they end up depends on the size and also which other devices are
present.

> and also, i wonder why qemu's vga pci bar address is different from
> virtualbox's vga pci bar address though
> both of devices are classified as same 'vga' device(class id number :
> 0x30)

There is no need for it to have a fixed address.

> (in Virtualbox, VGA PIC BAR ADDRESS always starts from e0000000 and it
> is VBE standard)

I doubt it is VBE standard.

cheers,
  Gerd






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