Ubuntu – What does the following dmesg output means

dmesgfirmwarekernel

I am not sure what does this following means:-

[    0.652039] ACPI: Added _OSI(Module Device)
[    0.652044] ACPI: Added _OSI(Processor Device)
[    0.652049] ACPI: Added _OSI(3.0 _SCP Extensions)
[    0.652054] ACPI: Added _OSI(Processor Aggregator Device)
[    0.656286] ACPI: EC: Look up EC in DSDT
[    0.660361] ACPI: Executed 1 blocks of module-level executable AML code
**[    0.720310] [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored**
[    0.721539] ACPI: SSDT 000000009ce70798 00727 (v01  PmRef  Cpu0Cst 00003001 INTL 20100121)
[    0.722623] ACPI: Dynamic OEM Table Load:
[    0.722630] ACPI: SSDT           (null) 00727 (v01  PmRef  Cpu0Cst 00003001 INTL 20100121)
[    0.752832] ACPI: SSDT 000000009ce71a98 00303 (v01  PmRef    ApIst 00003000 INTL 20100121)

What kind of bug is this? Does this bug affects my system performance.

Best Answer

For what I can understand it means that a query from the Bios/Firmware related to the ACPI (If you are running a laptop it means the battery, if you are running a Desktop PC it means a UPS or similar) is not recognized.

What Ubuntu did there was ignore the query to not cause problems. Some of the stuff you might see because of this are:

  1. Ubuntu battery state does not detect when the battery has been disconnected. Showing you still the same "Battery Connected" symbol.

  2. Battery charging notification is not updated correctly.

This does not mean the battery will not charge correctly, or that it did not detect the state of the battery correctly, it just means that in the Desktop you will not see it correctly. This does not even mean it will not show correctly to you.

For performance related stuff, you will not suffer any performance problems. It will be running the same as always.

Basically this comes from a BIOS, first assuming that the OS is Windows and then doing a query to it to confirm some information.

Anyway don't worry about it, Ubuntu and any other Linux distro can effectively just tell the BIOS that it is in fact Windows and get the correct query from it. Dmesg and the booting system just post that message there to notify you about the BIOS asking something to the OS (Remember, it is assuming is Windows) and Linux trying to fake it so the BIOS sends the complete query. This is a reason why BIOS manufacturers should not assume that the only hardware they will work on is Windows.

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