The _STA ASL method can often be used to check for run-time conditions. Can't remember off-hand how that works for processor objects. There are typically three ways this is handled:
1) The _STA method can read some register directly that determines this. 2) The firmware creates a memory Operation Region which is essentially a buffer full of configuration settings and the _STA references that. 3) The firmware patches the AML during boot with the actual number of cores, or the return status values. Tim -----Original Message----- From: Brian J. Johnson [mailto:[email protected]] Sent: Friday, September 19, 2014 7:08 AM To: [email protected] Subject: Re: [edk2] UEFI and ACPI BIOSes often have boot-time code which tweaks the static ACPI tables generated by iasl to reflect the current hardware. For instance, it may mark missing CPUs as "disabled." It's also possible (although a lot of work) to generate the binary ACPI data (AML) on the fly. I'm not aware of any standardized UEFI functions to do this, however. It's a very platform-specific thing. Brian On 09/19/2014 12:56 AM, Neeraj Ladkani wrote: > You mean changing tables during subsequent boot or runtime? IMHO, > During reboot, boot fw can choose which table to populate . > > Neeraj > > On Sep 19, 2014 11:10 AM, "Narinder Dhillon" <[email protected] > <mailto:[email protected]>> wrote: > > Hi All, > > In order to add ACPI tables to UEFI, iasl compiler has to be > downloaded from acpica.org <http://acpica.org>. > UEFI build compiles the tables, which makes the configuration static. > Is there any way to change this configuration from UEFI prompt or by > calling UEFI functions ? > For example, I have a 8 core ARMv8 ACPI table but I want to boot > only 4 cores. Is it possible to change this on the fly without > editing and recompiling the ACPI tables ? > > Thanx. > > > ------------------------------------------------------------------------------ > Slashdot TV. Video for Nerds. Stuff that Matters. > > http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk > _______________________________________________ > edk2-devel mailing list > [email protected] > <mailto:[email protected]> > https://lists.sourceforge.net/lists/listinfo/edk2-devel > > > > ---------------------------------------------------------------------- > -------- Slashdot TV. Video for Nerds. Stuff that Matters. > http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg. > clktrk > > > > _______________________________________________ > edk2-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/edk2-devel > -- "It's OK to be stuck. 99% of the time in your own [research] work, you're stuck." -- Mark Lawrence ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that Matters. http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk _______________________________________________ edk2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/edk2-devel ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that Matters. http://pubads.g.doubleclick.net/gampad/clk?id=160591471&iu=/4140/ostg.clktrk _______________________________________________ edk2-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/edk2-devel
