[syslinux] Measuring boot time

[Geert Stappers]

On Mon, Oct 05, 2015 at 08:36:17PM +0000, Tal Lubko via Syslinux wrote:
> Hi
> Some time ago I wrote this mailing list about some extra time that it
> takes for my system to boot

And meanwhile there where many, many e-mail on this mailinglist.
So thank you for bringing another (good) reason to reply _below_ the text.


> and I don't know where it came from.

Yes, please elaborate.


> I'm using a custom BIOS which loads at 1 second and now I've found out
> that it takes for the bootloader and OS an extra 1 second to load when
> keyboard is disconnected.I got from the BIOS engineer the following
> explanation and steps to take:
> In syslinux make sure that it doesn???t use the KBC at all.
> KBC functions will timeout when a KBC is not present.
> GATEA20 (address line A20 wrap around 8086 compatibility gate) must
> not be controlled by KBC as first option. No menu stuff or something
> needing keyboard should be used.
> 
> The GATEA20 should be enabled as follows:
> 
> 1) Test if A20 is already enabled. If enabled goto 7.
> 2) Do BIOS int 0x15 function 0x2401 to enable GATEA20.
> 3) Test if A20 is enabled. If enabled go to 7.
> 4) Do port 0x92 (FASTA20) enable.
> 5) Test if A20 is enabled. If enabled go to 7.
> 6) Error!!
> 7) A20 is enabled. Done.
> However, I'm not sure what's the best way to do that.I've seen that
> there is GATEA20 related code only in GPXE branch but I'm not using
> GPXE.
> Any suggestions?

Another BIOS???


> Best regards,Tal