Am Dienstag, den 19.03.2013, 19:17 -0400 schrieb Kevin O'Connor:
On Mon, Mar 18, 2013 at 11:57:31AM +0100, Paul Menzel wrote:
Dear SeaBIOS folks,
looking at
$ more src/Kconfig […] config AHCI depends on DRIVES bool "AHCI controllers" default y help Support for AHCI disk code. […]
disabling the »Drive interface« (which sets(?) `DRIVES`) in the menu BIOS interfaces, support for booting from an AHCI device is disabled too.
The dependency is there because there is no use in compiling in a disk device driver if there is no external interface to access disks. (What value would there be in having an AHCI driver if the BIOS doesn't support reading from disks?)
Hearing of filo or GRUB 2 as payload, I thought these interfaces are not needed for actual booting. But assuming is not good as Peter pointed out.
So for my understanding, in the current implementation SeaBIOS uses its own BIOS interfaces although strictly it would not be necessary. Is that correct?
I don't understand your question. Sometimes SeaBIOS calls external 16bit disk interfaces when it wishes to read from a drive - but it does this only for compatibility (to handle the cases where an option ROM could have hooked the 16bit disk interrupt and substituted its own code in place of the SeaBIOS code). This is not related to the Kconfig dependency however (see above).
I did not think of the option ROM. Thanks for mentioning it.
Thanks,
Paul