Latitude 7280: Problem with backlight control

[Dell7280pl]

Okay, that's hard
it is a pity there is no way to solve this problem

[Baio77]

The problem surely depends on the ACPI of your DELL, in this case the DSDT. Here in the code is the explanation:

 

//
DefinitionBlock("", "SSDT", 2, "OCLT", "OCWork", 0)
{
    External (_SB.ACOS, IntObj)
    External (_SB.ACSE, IntObj)
    
    Scope (\)
    {
        If (_OSI ("Darwin"))
        {
            \_SB.ACOS = 0x80
            \_SB.ACSE = 0 //ACSE=0:win7;;ACSE=1:win8 
        }
    }
}
//EOF

 

This you might try to vary

 

ACSE=0:win7;
ACSE=1:win8

 

In SSDT single is Zero set, you have to try with One
https://github.com/Lorys89/DELL_LATITUDE_7280/blob/main/EFI/OC/ACPI/SSDT-DELL-LATITUDE-7280.dsl 

 

Scope (\)

{

If (_OSI ("Darwin"))

{

HPTE = Zero

SDM1 = Zero

\_SB.ACOS = 0x80

\_SB.ACSE = Zero

}

Test this EFI if start ioreg https://drive.google.com/drive/folders/1ZNwe7Rw2ZXV0fbzpnRq43uhnUIDqp6Nh?usp=sharing

[Dell7280pl]

Your EFI is the same as mine, nothing has changed