On T60/T61/X61 thinkpad_acpi fills the log with these messages every 5 second: [ 2066.078276] thinkpad_acpi: acpi_evalf(BCTG, dd, ...) failed: AE_NOT_FOUND [ 2066.078287] ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCTG: evaluate failed [ 2066.078329] thinkpad_acpi: acpi_evalf(BCSG, dd, ...) failed: AE_NOT_FOUND [ 2066.078335] ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCSG: evaluate failed [ 2071.081787] thinkpad_acpi: acpi_evalf(BCTG, dd, ...) failed: AE_NOT_FOUND [ 2071.081795] ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCTG: evaluate failed [ 2071.081828] thinkpad_acpi: acpi_evalf(BCSG, dd, ...) failed: AE_NOT_FOUND [ 2071.081833] ACPI: \_SB_.PCI0.LPC_.EC__.HKEY: BCSG: evaluate failed 'This happens with stock Lenovo BIOS and Libreboot.
Thinkpad X200 is also affected, but message shows up only two times while booting (stock hardware, stock bios). Kernel is: 5.0.2-arch1-1-ARCH #1 SMP PREEMPT Thu Mar 14 18:47:49 UTC 2019 x86_64 GNU/Linux