MP Spec: Correct the Virtual Wire assignment
Virtual Wire mode is set by writing 0 to the the MPTable
Feature2 bit field 'IMCR'. The virtualwire variable was
initially defined as writing a 1 to this bit field which
would actually set PIC mode instead of Virtual Wire mode.
However, nearly every mainboard called the MPTables with
virtualwire = 0, which actually had the effect of setting
Virtual Wire mode. I am correcting the definition but
leaving the call to write the MPTables with virtualwire = 0,
which is how most mainboards are already setting the tables
up.
See the MP Spec table 4-1 for more details:
Bit 7: IMCRP. When the IMCR presence bit is
set, the IMCR is present and PIC Mode is
implemented; otherwise, Virtual Wire Mode is
implemented.
http://download.intel.com/design/archives/processors/pro/docs/24201606.pdf
Change-Id: I039d88134aabd55166c2b68aa842bacbfcc0f42b
Signed-off-by: Mike Loptien <mike.loptien@se-eng.com>
Reviewed-on: http://review.coreboot.org/5977
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
2 files changed