If BIOS invokes _OSI(Linux), the kernel response
depends on what the ACPI DMI list knows about the system,
and that is reflectd in dmesg:
1) System unknown to DMI:
ACPI: BIOS _OSI(Linux) query ignored
ACPI: DMI System Vendor: LENOVO
ACPI: DMI Product Name: 7661W1P
ACPI: DMI Product Version: ThinkPad T61
ACPI: DMI Board Name: 7661W1P
ACPI: DMI BIOS Vendor: LENOVO
ACPI: DMI BIOS Date: 10/18/2007
ACPI: Please send DMI info above to linux-acpi@vger.kernel.org
ACPI: If "acpi_osi=Linux" works better, please notify linux-acpi@vger.kernel.org
2) System known to DMI, but effect of OSI(Linux) unknown:
ACPI: DMI detected: Lenovo ThinkPad T61
...
ACPI: BIOS _OSI(Linux) query ignored via DMI
ACPI: If "acpi_osi=Linux" works better, please notify linux-acpi@vger.kernel.org
3) System known to DMI, which disables _OSI(Linux):
ACPI: DMI detected: Lenovo ThinkPad T61
...
ACPI: BIOS _OSI(Linux) query ignored via DMI
4) System known to DMI, which enable _OSI(Linux):
ACPI: DMI detected: Lenovo ThinkPad T61
ACPI: Added _OSI(Linux)
...
ACPI: BIOS _OSI(Linux) query honored via DMI
cmdline overrides take precidence over the built-in
default and the DMI prescribed default.
cmdline "acpi_osi=Linux" results in:
ACPI: BIOS _OSI(Linux) query honored via cmdline
Signed-off-by: Len Brown <len.brown@intel.com>
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