diff options
| author | Bob Moore | 2009-05-21 11:05:03 +0800 |
|---|---|---|
| committer | Len Brown | 2009-05-27 00:41:34 -0400 |
| commit | b1cd843be74ba0dcc6c42db7b11b76d63be149f6 (patch) | |
| tree | 6a3df5446a8fe67d4b757fc0553c6e5e3097c0c2 /drivers/acpi | |
| parent | 3362a6badb4fe75e198885b125b21ccf846861b4 (diff) | |
ACPICA: Disable preservation of SCI enable bit (SCI_EN)
Preserving this bit breaks some machines. Not preserving this bit
seems to work OK in all cases, even though this goes against the
ACPI spec.
http://bugzilla.kernel.org/show_bug.cgi?id=13289
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/acpica/aclocal.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h index 882b4b55867f..ee986edfa0da 100644 --- a/drivers/acpi/acpica/aclocal.h +++ b/drivers/acpi/acpica/aclocal.h @@ -789,11 +789,14 @@ struct acpi_bit_register_info { /* For control registers, both ignored and reserved bits must be preserved */ /* - * The ACPI spec says to ignore PM1_CTL.SCI_EN (bit 0) - * but we need to be able to write ACPI_BITREG_SCI_ENABLE directly - * as a BIOS workaround on some machines. + * For PM1 control, the SCI enable bit (bit 0, SCI_EN) is defined by the + * ACPI specification to be a "preserved" bit - "OSPM always preserves this + * bit position", section 4.7.3.2.1. However, on some machines the OS must + * write a one to this bit after resume for the machine to work properly. + * To enable this, we no longer attempt to preserve this bit. No machines + * are known to fail if the bit is not preserved. (May 2009) */ -#define ACPI_PM1_CONTROL_IGNORED_BITS 0x0200 /* Bits 9 */ +#define ACPI_PM1_CONTROL_IGNORED_BITS 0x0200 /* Bit 9 */ #define ACPI_PM1_CONTROL_RESERVED_BITS 0xC1F8 /* Bits 14-15, 3-8 */ #define ACPI_PM1_CONTROL_PRESERVED_BITS \ (ACPI_PM1_CONTROL_IGNORED_BITS | ACPI_PM1_CONTROL_RESERVED_BITS) |