[Solved] E6220: Brightness toggle via Fn keys (UP & DOWN)

[Growtopia Jaw]

I can't seem to get the brightness Fn keys (UP & DOWN) working after upgrading to Mojave. I have been using the DSDT.aml from Jake Lo's Dell Latitude/Inspiron/Precision/Vostro/XPS -  Clover Guide "E6220_A13_HS.zip" as I found it to be working well with macOS High Sierra 10.13.6. I've also tried Hervé's DSDT.aml but none of them worked under High Sierra and Mojave, for me at least.

 

I've opened up the DSDT.aml MaciASL and found that this code seems to be responsible for the brightness keys

            Method (_Q66, 0, NotSerialized)  // _Qxx: EC Query, xx=0x00-0xFF
            {
                If ((ECRD != One))
                {
                    Return (Zero)
                }

                NEVT ()
                Return (Zero)
            }

 

This code is present in both Hervé and Jake Lo's DSDT.aml and for some reason only Jake Lo's version worked under High Sierra for me.

 

I also found this tutorial from InsanelyMac, GUIDE: How to Fix Brightness hotkeys in DSDT but the guide isn't going to work for the E6220 as both Fn UP and Fn DOWN keys gave the same response, "_Q66"

 

This is what I've obtained from debugging the DSDT.aml with the help of ACPIDebug.kext and patching DSDT.aml with "Add DSDT Debug Methods" and "Instrument EC Queries"

 

Growtopias-MacBook-Pro:MountEFI-update growtopiajaw$ log show --last 5 | grep ACPIDebug
2021-05-26 22:55:06.733105+0800 0x18e      Default     0x0                  0      0    kernel: (ACPIDebug) ACPIDebug: "EC _Q66 enter"
2021-05-26 22:55:06.912525+0800 0x18e      Default     0x0                  0      0    kernel: (ACPIDebug) ACPIDebug: "EC _Q66 enter"
2021-05-26 22:55:07.092614+0800 0x18e      Default     0x0                  0      0    kernel: (ACPIDebug) ACPIDebug: "EC _Q66 enter"
2021-05-26 22:55:10.467899+0800 0x18e      Default     0x0                  0      0    kernel: (ACPIDebug) ACPIDebug: "EC _Q66 enter"
2021-05-26 22:55:10.668061+0800 0x18e      Default     0x0                  0      0    kernel: (ACPIDebug) ACPIDebug: "EC _Q66 enter"

As you can see, the detected keystrokes are exactly the same but in reality, those are 2 different keys Fn UP & Fn Down

 

So, in conclusion has anyone managed to get the brightness keys working under Mojave?

 

Thanks.

[Hervé]

Look up my recent Mojave and Catalina updates in my E6220 guide. They offer an installation free of patched DSDT, in UEFI mode and the posted pack contains all the SSDT tables + ACPI renamings in the Clover config to cater for brightness keys. You'll find the necessary code for Fn-UP/Fn-DOWN operation in the SSDT-Q66 table.

[Growtopia Jaw]

Hi, thanks for the reply. I've found the relevant code and made some changes. Brightness works normally via the function key now.

 

Thanks!