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@xxxxxxxxxxxxx>
---
drivers/acpi/osi.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c
index 76998a5..a22fe3a 100644
--- a/drivers/acpi/osi.c
+++ b/drivers/acpi/osi.c
@@ -57,6 +57,14 @@ osi_setup_entries[OSI_STRING_ENTRIES_MAX] __initdata = {
{"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)
--
2.7.4
--
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