ACPI / OSI: Add OEM _OSI strings to disable NVidia RTD3
A number of Dell systems require an OEM _OSI string "Linux-Dell-Video"
as a BIOS workaround to disable RTD3 which causes systems hangs when
NVidia graphics cards are installed. The affected Dell systems are
with system IDs: 0818, 0819, 0820, 0850, 0851, 086F, 0870, 0885 and
0886.
The form of the OEM _OSI strings is defined by each OEMs and is
discussed in Documentation/acpi/osi.txt.
Signed-off-by: Alex Hung <alex.hung@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c
index 76998a5..8a8f435 100644
--- a/drivers/acpi/osi.c
+++ b/drivers/acpi/osi.c
@@ -57,6 +57,15 @@
{"Processor Device", true},
{"3.0 _SCP Extensions", true},
{"Processor Aggregator Device", true},
+ /*
+ * Linux-Dell-Video is used by BIOS to disable RTD3 for NVidia graphics
+ * cards as RTD3 is not supported by drivers now. Systems with NVidia
+ * cards will hang without RTD3 disabled.
+ *
+ * Once NVidia drivers officially support RTD3, this _OSI strings can
+ * be removed if both new and old graphics cards are supported.
+ */
+ {"Linux-Dell-Video", true},
};
static u32 acpi_osi_handler(acpi_string interface, u32 supported)