ACPI Suspend: Enable ACPI during resume if SCI_EN is not set
commitd0c71fe7ebc180f1b7bc7da1d39a07fc19eec768
authorRafael J. Wysocki <rjw@sisk.pl>
Fri, 3 Oct 2008 22:05:05 +0000 (4 00:05 +0200)
committerLen Brown <len.brown@intel.com>
Fri, 17 Oct 2008 00:45:54 +0000 (16 20:45 -0400)
tree9ffc49ac55a7a486f92944e7354593db313e7f7b
parenta6629105dd03d370fcb31e97bddf223fa4bb651e
ACPI Suspend: Enable ACPI during resume if SCI_EN is not set

On some machines, like for example MSI Wind U100, the BIOS doesn't
enable ACPI before returning control to the OS, which sometimes
causes resume to fail.  This is against the ACPI specification,
which clearly states that "When the platform is waking from an S1, S2
or S3 state, OSPM assumes the hardware is already in the ACPI mode
and will not issue an ACPI_ENABLE", but it won't hurt to check the
SCI_EN bit and enable ACPI during resume from S3 if this bit is not
set.

Fortunately, we already have acpi_enable() for that, so use it in the
resume code path, before executing _BFS, in analogy with the
resume-from-hibernation code path.

NOTE: We aren't supposed to set SCI_EN directly, because it's owned
by the hardware.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Pavel Machek <pavel@suse.cz>
Signed-off-by: Len Brown <len.brown@intel.com>
drivers/acpi/sleep/main.c