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authorMike Loptien <mike.loptien@se-eng.com>2014-06-11 14:20:48 -0600
committerMike Loptien <mike.loptien@se-eng.com>2014-06-16 18:14:35 +0200
commitd0167d3ae268e3fcdef5c02e381b47dbb04ab1a4 (patch)
tree265882f5cd1336d324a487d022ed6011e5404506 /documentation/Makefile
parent915973406544d1d6a60a539ad9fb8a33c3caf2c9 (diff)
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>
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