ACPI: Make _OSI(Linux) a special case

_OSI("Linux") is like _OS("Linux"), it is ill-defined and
virtually no BIOS vendors test interaction with it.
As a result, it can do more damage than good because
it causes the BIOS to follow un-tested paths.

Recently, several machines have turned up that erroneously
test this string in a way which causes them to _not_ test other
compatibility strings, including the ZI9 and Toshiba.
So it appears that this bad code has made it into
a BIOS vendor's reference BIOS.

Linux has no choice but to stop advertising compatibility
with _OSI string "Linux" - as there are an unbounded
number of possible incompatibilities going forward.

But some BIOSes have already shipped which do use it
for things like conditionally re-enabling video on resume
from S3.  (Too bad they didn't do that unconditionally)

Add special case code for _OSI(Linux)
Squawk to dmesg if _OSI(Linux) is requested
Add DMI list both to enable and disable _OSI(Linux)
But for now, keep the default enabled via
#define OSI_LINUX_ENABLED.

http://bugzilla.kernel.org/show_bug.cgi?id=7787

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/drivers/acpi/utilities/uteval.c b/drivers/acpi/utilities/uteval.c
index a10120ad6982..8ec6f8e48138 100644
--- a/drivers/acpi/utilities/uteval.c
+++ b/drivers/acpi/utilities/uteval.c
@@ -62,7 +62,6 @@ acpi_ut_translate_one_cid(union acpi_operand_object *obj_desc,
 static char *acpi_interfaces_supported[] = {
         /* Operating System Vendor Strings */
 
-        "Linux",
         "Windows 2000",
         "Windows 2001",
         "Windows 2001 SP0",