• Bernhard Kaindl's avatar
    [PATCH] x86: Save and restore the fixed-range MTRRs of the BSP when suspending · 3ebad590
    Bernhard Kaindl authored
    Note: This patch didn'nt need an update since it's initial post.
    
    Some BIOSes may modify fixed-range MTRRs in SMM, e.g. when they
    transition the system into ACPI mode, which is entered thru an SMI,
    triggered by Linux in acpi_enable().
    
    SMIs which cause that Linux is interrupted and BIOS code is
    executed (which may change e.g. fixed-range MTRRs) in SMM may
    be raised by an embedded system controller which is often found
    in notebooks also at other occasions.
    
    If we would not update our copy of the fixed-range MTRRs before
    suspending to RAM or to disk, restore_processor_state() would
    set the fixed-range MTRRs of the BSP using old backup values
    which may be outdated and this could cause the system to fail
    later during resume.
    
    This patch ensures that our copy of the fixed-range MTRRs
    is updated when saving the boot processor state on suspend
    to disk and suspend to RAM.
    
    In combination with other patches this allows to fix s2ram
    and s2disk on the Acer Ferrari 1000 notebook and at least
    s2disk on the Acer Ferrari 5000 notebook.
    Signed-off-by: default avatarBernhard Kaindl <bk@suse.de>
    Signed-off-by: default avatarAndi Kleen <ak@suse.de>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andi Kleen <ak@suse.de>
    Cc: Dave Jones <davej@codemonkey.org.uk>
    3ebad590
suspend.c 6.26 KB