[SeaBIOS] Non-PNP legacy option rom scan and init

Kevin O'Connor kevin at koconnor.net
Sun May 8 20:17:04 CEST 2011

On Sun, May 08, 2011 at 07:50:12PM +0200, Sebastian Herbszt wrote:
> Kevin O'Connor wrote:
> >On Thu, May 05, 2011 at 12:53:36AM +0200, Sebastian Herbszt wrote:
> >>Got a pointer in the BBS spec?
> >Section 5.2.3:
> Chapter 6 describes the POST sequence:
> - Initializing BAIDs, PnP Boot Devices
> - PnP Option ROM Initialization
> - INT 13h Device Controller Installation (BCV, Legacy ROM Scan, On-board ATA Support)
> - IPL processing
> So by the time the boot menu is displayed all BCVs and legacy roms
> should have already been called.

SeaBIOS shows the boot in "6.3 Check IPL Priority and BCV Priority"
which is between "6.2 PnP Option ROM Initialization" and "6.4 INT 13h
Device Controller Installation".

We want the boot menu to be able to configure which drive becomes the
C: drive, so the boot menu must be displayed prior to running the BCVs
and Legacy Option ROMs.

>This doesn't seem to be currently
> true for legacy roms. PnP roms are called but legacy roms are
> not. They are only called if they are selected from the boot menu.

All BCVs and legacy option roms are always called.  The only thing the
boot menu does is determine the order of their invocation.  (See
boot.c:boot_prep().)  If you have a counter-example then it is a bug
and must be fixed.


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