ZBook 15 ACPI Error in Linux kernel: [CFGD] is an unknown object

[Jeremy_Murphy]

The machine is a first-generation ZBook 15 with BIOS v1.40, which is the latest available.

Using Linux kernel 4.15.18, this appears in the kernel log at boot time:

[ 2.095932] ACPI: Thermal Zone [CPUZ] (65 C)
[ 2.110168] ACPI Error: [CFGD] Namespace lookup failure, AE_NOT_FOUND (20170728/psargs-364)
[ 2.110197] ACPI Error: Method parse/execution failed \_TZ.PSL, AE_NOT_FOUND (20170728/psparse-550)
[ 2.110222] ACPI Error: Method parse/execution failed \_TZ.GFXZ._PSL, AE_NOT_FOUND (20170728/psparse-550)
[ 2.110248] ACPI: Invalid passive threshold
[ 2.120238] thermal LNXTHERM:01: registered as thermal_zone1
[ 2.120257] ACPI: Thermal Zone [GFXZ] (53 C)
[ 2.135427] thermal LNXTHERM:02: registered as thermal_zone2
[ 2.135446] ACPI: Thermal Zone [EXTZ] (0 C)
[ 2.150638] thermal LNXTHERM:03: registered as thermal_zone3
[ 2.150658] ACPI: Thermal Zone [LOCZ] (0 C)
[ 2.155885] ACPI Error: [CFGD] Namespace lookup failure, AE_NOT_FOUND (20170728/psargs-364)
[ 2.156703] ACPI Error: Method parse/execution failed \_TZ.PSL, AE_NOT_FOUND (20170728/psparse-550)
[ 2.157502] ACPI Error: Method parse/execution failed \_TZ.BATZ._PSL, AE_NOT_FOUND (20170728/psparse-550)
[ 2.158298] ACPI: Invalid passive threshold
[ 2.168906] thermal LNXTHERM:04: registered as thermal_zone4
[ 2.169729] ACPI: Thermal Zone [BATZ] (30 C)
[ 2.170764] thermal LNXTHERM:05: registered as thermal_zone5
[ 2.171577] ACPI: Thermal Zone [PCHZ] (0 C)

The salient lines are those with "Error" in them.

I don't know a whole lot about ACPI, but using the Intel ACPI compiler/disassembler I dumped the ACPI table and disassembled it. In the definition block, CFGD is listed as unknown:

External (CFGD, UnknownObj)

Rui Zhang over on the Linux kernel bugzilla claims that this is due to buggy firmware:

This is caused by buggy firmware.
External (_PR_.CFGD, UnknownObj) should be used to refer to the CFGD object.

What do you think? If it is buggy firmware, I would really appreciate it if HP would fix it.

I can provide more system and ACPI details if required.

Thanks, cheers.

Jeremy Murphy

PS. I wasn't exactly sure which board to post this on, so this is a cross-post originally on Operating Systems.