efivars

[Greg KH]

On Thu, Sep 23, 2021 at 08:24:10AM -0400, Ruben Safir wrote:
> On 9/23/21 3:27 AM, FMDF wrote:
> > but it still needs to use UEFI at runtime.
> no if it is on a bios system

If you are using the old "BIOS" interface, there are still places where
that BIOS takes over control from the CPU and does things behind the
operating system's back.  There are also things that the BIOS does that
the operating system must talk to over time in order to coordinate
things like power management and "simple" things like powering off the
system (hint, that's not a simple thing).

So your old BIOS was still sitting there running and providing services
to the operating system just like UEFI does so today.  That has not
changed except that a number of the issues involved with that old
interface have been fixed up, and a number of new interfaces have been
added.

greg k-h