Dell Precision 5540 4k non-touch.

Latest bios as of Nov. 14 2019, kernel up to 5.3.11

The same with Ubuntu, see errors then trying to setup brightness

[ноя14 19:55] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.PEG0.PEGP.BRT6.LCD], AE_NOT_FOUND (20190703/psargs-330)
[ +0,000026] No Local Variables are initialized for Method [BRT6]
[ +0,000004] Initialized Arguments for Method [BRT6]: (2 arguments defined for method invocation)
[ +0,000001] Arg0: 00000000d9aa419b Integer 0000000000000001
[ +0,000009] Arg1: 00000000cd86c074 Integer 0000000000000000
[ +0,000011] ACPI Error: Aborting method \_SB.PCI0.PEG0.PEGP.BRT6 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000418] ACPI Error: Aborting method \EV5 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000419] ACPI Error: Aborting method \SMEE due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000289] ACPI Error: Aborting method \SMIE due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000208] ACPI Error: Aborting method \NEVT due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000172] ACPI Error: Aborting method \_SB.PCI0.LPCB.ECDV._Q66 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,811242] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.PEG0.PEGP.BRT6.LCD], AE_NOT_FOUND (20190703/psargs-330)
[ +0,000026] No Local Variables are initialized for Method [BRT6]
[ +0,000004] Initialized Arguments for Method [BRT6]: (2 arguments defined for method invocation)
[ +0,000002] Arg0: 00000000d9aa419b Integer 0000000000000002
[ +0,000008] Arg1: 00000000cd86c074 Integer 0000000000000000
[ +0,000012] ACPI Error: Aborting method \_SB.PCI0.PEG0.PEGP.BRT6 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000297] ACPI Error: Aborting method \EV5 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000175] ACPI Error: Aborting method \SMEE due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000184] ACPI Error: Aborting method \SMIE due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000272] ACPI Error: Aborting method \NEVT due to previous error (AE_NOT_FOUND) (20190703/psparse-529)
[ +0,000378] ACPI Error: Aborting method \_SB.PCI0.LPCB.ECDV._Q66 due to previous error (AE_NOT_FOUND) (20190703/psparse-529)