ec/system76/ec: Add manual fan control

[crawfxrd]

system76/ec#512 added a manual fan control option.

In PWM control mode, the system firmware or OS is responsible for setting the fan target duty to manage thermals. CTR0 in the EC code determines the maximum valid PWM duty, which is hard-coded to 255.

RPM target is not supported.

Requires: system76/ec#512

[leviport]

This doesn't seem to compiling for me, using the firmware-open build.sh script. My submodules are updated, and I tried both with this branch checked out in the Coreboot submodule with master checked out in firmware-open, and with the fan-manual branch of firmware-open checked out.

Error output snippet below:

Click to expand

coreboot toolchain v2024-07-03_7c1813c137
    HOSTCC     cbfstool/linux_trampoline.o
    HOSTCC     cbfstool/cbfs-payload-linux.o
    HOSTCC     cbfstool/compress.o
    HOSTCC     cbfstool/lz4.o
    HOSTCC     cbfstool/lz4hc.o
    HOSTCC     cbfstool/lz4frame.o
    HOSTCC     cbfstool/xxhash.o
    HOSTCC     cbfstool/lz4_wrapper.o
    HOSTCC     cbfstool/lzma.o
    HOSTCC     cbfstool/LzFind.o
    HOSTCC     cbfstool/LzmaDec.o
    HOSTCC     cbfstool/LzmaEnc.o
    MAKE       /home/levi/repos/firmware-open/coreboot/vboot_lib/libvboot_host.a
    CC         bootblock/arch/x86/gdt_init.o
    CC         bootblock/arch/x86/id.o
    CC         bootblock/arch/x86/idt.o
    CC         bootblock/cpu/x86/early_reset.o
    CC         bootblock/cpu/x86/entry16.o
    CC         bootblock/cpu/x86/entry32.o
Error    6154 - Warnings detected during compilation (reporting warnings as errors)

dsdt.asl     28:    Name (RBUF, ResourceTemplate ()
Remark   2173 -             ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PERC._CRS)

dsdt.asl    177:  Name (MCRS, ResourceTemplate ()
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0._CRS)

dsdt.asl    310:   Name (BUF0, ResourceTemplate ()
Remark   2173 -            ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.PDRC._CRS)

dsdt.asl    351:  OperationRegion (PCRD, SystemMemor    CC         bootblock/cpu/x86/reset16.o
y, GPCR (Arg0, Arg1) + Arg2, 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.RPCR)

dsdt.asl    360:  OperationRegion (PCRD, SystemMemory, GPCR (Arg0, Arg1) + Arg2, 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.APCR)

dsdt.asl    370:  OperationRegion (PCRD, SystemMemory, GPCR (Arg0, Arg1) + Arg2, 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.OPCR)

dsdt.asl    404:   Name (DSUU, ToUUID("f6c13ea5-65cd-461f-ab7a-29f7e8d5bd61"))
Remark   2184 -                                       Unknown UUID string ^

dsdt.asl    459:   Name (DSUU, ToUUID("f6c13ea5-65cd-461f-ab7a-29f7e8d5bd61"))
Remark   2184 -                                       Unknown UUID string ^

dsdt.asl    517:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GRXS)

dsdt.asl    527:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GTXS)

dsdt.asl    536:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.STXS)

dsdt.asl    545:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.CTXS)

dsdt.asl    554:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GPMO)

dsdt.asl    564:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GTXE)

dsdt.asl    574:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GRXE)

dsdt.asl    584:  OperationRegion (PREG, SystemMemory, GADD (Arg0), 4)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.GSCI)

dsdt.asl    833:  Name (UUID, ToUUID ("A69F886E-6CEB-4594-A41F-7B5DCE24C553"))
Remark   2184 -                                       Unknown UUID string ^

dsdt.asl    864:  Name (IQAA, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    869:  Name (IQAP, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    874:  Name (IQBA, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    879:  Name (IQBP, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    884:  Name (IQCA, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    889:  Name (IQCP, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    894:  Name (IQDA, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl    899:  Name (IQDP, Package () {
Remark   2173 -           ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.IRQM)

dsdt.asl   1256:  OperationRegion (PSCR, SystemMemory, (Arg2 << 16) + Local0, 0x10)
Remark   2173 -                      ^ Creation of named objects within a method is highly inefficient, use globals or method local variables instead (\_SB.PCI0.UPWE)

dsdt.asl   1839:  Method (_SFD, 2, Serialized) {
Warning  3133 -             ^ Unknown reserved name (_SFD)

dsdt.asl   2362:    ToUUID("6211e2c0-58a3-4af3-90e1-927a4e0c55a4"),
Remark   2184 -                            Unknown UUID string ^

dsdt.asl   2369:    ToUUID("efcc06cc-73ac-4bc3-b    CC         bootblock/soc/intel/common/block/cpu/car/cache_as_ram.o
ff0-76143807c389"),
Remark   2184 -                            Unknown UUID string ^

ASL Input:     dsdt.asl -   43619 bytes   1373 keywords      0 source lines

Compilation failed. 1 Errors, 1 Warnings, 28 Remarks
No AML files were generated due to compiler error(s)

[sam-at-dao]

Howdy

I'm on a Lemur Pro, lemp13, running current firmware; Firmware Manager reports 2025-07-24_c242738 with nothing newer to apply.

Under sustained CPU load the automatic fan curve doesn't keep this machine out of thermal throttle.
The system reported temperature hits 100°C+ and clocks floor around 260MHz.
My daily workaround is Fn+1, to turn on the fan manually when it starts to throttle. It works, but max is the only setting it has, around 9100 RPM on this machine, and it's loud.
A target PWM path would let me hold the machine at a sustainable speed rather than choosing between throttling and full tilt.

Chasing a scriptable alternative, the chain appears to be:

1. system76/ec#512 merged EC-side target PWM support in January 2025
2. this PR would expose it through ACPI
3. system76-acpi-dkms PR #18 is waiting on this to land before it can expose a writable pwm1/pwm1_enable.

Today pwm1 is mode 444 with no pwm1_enable at all, so fancontrol and pwmconfig can't work even in principle. So this PR can unblock all that downstream.

Can I help test this on real hardware (Ive got a lemp13) so this can land and propagate?