How to use AMD P-State in Linux

jonathon · June 4, 2022, 10:31am

Still seems to be present for me.

Is this just a Manjaro change?

Stephane · June 4, 2022, 10:47am

with manjaro kernel 5.17.12 , this is ok , still amd-pstate
( can change from start acpi-cpufreq to amd-pstate )

with blacklist acpi_cpufreq on boot , nor more acpi-cpufreq with 5.18.1 ( manjaro or archlinux )
cannot boot directly , and so cant change to amd-pstate

solution :
add amd_pstate in module in file mkinitcpio.conf → ok manjaro 5.18.1

pebcak · June 4, 2022, 11:47am

I’m not getting this to work:

MODULES=(amd_pstate)

then sudo mkinitcpio -P

After reboot:

$ cpupower frequency-info 
analyzing CPU 0:
  no or unknown cpufreq driver is active on this CPU
  CPUs which run at the same hardware frequency: Not Available
  CPUs which need to have their frequency coordinated by software: Not Available
  maximum transition latency:  Cannot determine or is not supported.
Not Available
  available cpufreq governors: Not Available
  Unable to determine current policy
  current CPU frequency: Unable to call hardware
  current CPU frequency:  Unable to call to kernel
  boost state support:
    Supported: yes
    Active: no

Have I missed any step?

Edit:

Trying to load amd_pstate manually:

# sudo modprobe -r acpi_cpufreq
# sudo modprobe amd_pstate
modprobe: ERROR: could not insert 'amd_pstate': No such device

moson · June 4, 2022, 12:21pm

What processor do you have?

Try loading the module like this for some more verbose output:

sudo modprobe amd_pstate dyndbg==pmf -v

Then check dmesg for any messages…

Stephane · June 4, 2022, 12:30pm

you need to boot on current kernel or zen kernel , not LTS ( no amd_pstate module inside )
check also for boot grub kernel & UEFI motherboard ( CPPC on auto or enable )
“amd_pstate.enable=1 amd_pstate.shared_mem=1”

sudo cpupower frequency-info
sudo turbostat
cat  /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver

jonathon · June 4, 2022, 12:51pm

The only thing I had to do was add amd_pstate.shared_mem=1 to the GRUB boot line, no messing around with modules or anything else.

pebcak · June 4, 2022, 12:53pm

System:
  Kernel: 5.18.1-zen1-1-zen arch: x86_64 bits: 64 compiler: gcc v: 12.1.0
    parameters: BOOT_IMAGE=/boot/vmlinuz-linux-zen
    root=UUID=920fc5a6-a736-43bf-a799-127e270776f0 rw
    lsm=landlock,lockdown,yama,apparmor,bpf loglevel=3
  Console: pty pts/6 wm: gnome-shell DM: GDM v: 42.0 Distro: Arch Linux
Machine:
  Type: Laptop System: LENOVO product: 82A2 v: Yoga Slim 7 14ARE05
    serial: <filter> Chassis: type: 10 v: Yoga Slim 7 14ARE05 serial: <filter>
  Mobo: LENOVO model: LNVNB161216 v: SDK0J40709 WIN serial: <filter>
    UEFI: LENOVO v: DMCN41WW date: 02/11/2022

Thanks @moson and @Stephane for the replies!

I’ll take your suggestions one at the time.

CPU:
  Info: model: AMD Ryzen 7 4800U with Radeon Graphics socket: FP6 bits: 64
    type: MT MCP arch: Zen 2 family: 0x17 (23) model-id: 0x60 (96) stepping: 1
    microcode: 0x8600106
  Topology: cpus: 1x cores: 8 tpc: 2 threads: 16 smt: enabled cache:
    L1: 512 KiB desc: d-8x32 KiB; i-8x32 KiB L2: 4 MiB desc: 8x512 KiB
    L3: 8 MiB desc: 2x4 MiB
  Speed (MHz): avg: 1776 high: 1797 min/max: N/A base/boost: 1800/4300
    volts: 1.2 V ext-clock: 100 MHz cores: 1: 1466 2: 1797 3: 1797 4: 1797
    5: 1797 6: 1797 7: 1797 8: 1797 9: 1797 10: 1797 11: 1797 12: 1797
    13: 1797 14: 1797 15: 1797 16: 1797 bogomips: 57496

Here is the output of:

sudo modprobe amd_pstate dyndbg==pmf -v

# modprobe amd_pstate dyndbg==pmf -v 
     insmod /lib/modules/5.18.1-zen1-1-zen/kernel/drivers/cpufreq/amd_pstate.ko.zst dyndbg==pmf
modprobe: ERROR: could not insert 'amd_pstate': No such device

and this is what I get from dmesg:

[ 687.287933] amd_pstate:amd_pstate_init: amd_pstate: the _CPC object is not present in SBIOS

and also from journalctl:

arch kernel: amd_pstate:amd_pstate_init: amd_pstate: the _CPC object is not present in SBIOS

From the output posted above, does it mean that amd_pstat is not supported on this motherboard? I haven’t seen anything in the settings related to CPPC.

pebcak · June 4, 2022, 12:55pm

@jonathon
Would you be kind and have a look at my previous post?

jonathon · June 4, 2022, 12:57pm

Looks related to this:

Your UEFI might not support it, or doesn’t expose the option?

pebcak · June 4, 2022, 12:59pm

I am inclined to the former.

If it is supported, I am not sure how I should make it visible.

I should reboot into --frimware-setup and have a look.

moson · June 4, 2022, 12:59pm

Yepp, the Lenovo’s don’t seem to have this options available in the BIOS and it seems to be disabled currently. You’d need to wait for another firmware/BIOS version.

I’ve actually created a thread on the lenovo forum’s about this some time ago.
You might want to add a post there hoping that this gets a bit more attention

https://forums.lenovo.com/t5/Other-Linux-Discussions/amd-pstate-driver-support-for-AMD-laptops/m-p/5135917

jonathon · June 4, 2022, 1:04pm

This tool might be useful:

But be warned, it exposes some very dangerous options!

pebcak · June 4, 2022, 1:05pm

That explains the whole thing then. It’ a pitty!

That’s great!

Thanks for the link! I’ll have a look.

My current firmware version:

UEFI: LENOVO v: DMCN41WW date: 02/11/2022

Hopefully / wishfully they release one soon with CPPC support.

pebcak · June 4, 2022, 1:08pm

Thanks @jonathon for the tips!
I’ll have a look!
Let’s see if can gather enough courage to implement such a thing

pebcak · June 4, 2022, 1:17pm

The current state of affairs on the system:

 cpupower frequency-info 
analyzing CPU 0:
  no or unknown cpufreq driver is active on this CPU
  CPUs which run at the same hardware frequency: Not Available
  CPUs which need to have their frequency coordinated by software: Not Available
  maximum transition latency:  Cannot determine or is not supported.
Not Available
  available cpufreq governors: Not Available
  Unable to determine current policy
  current CPU frequency: Unable to call hardware
  current CPU frequency:  Unable to call to kernel
  boost state support:
    Supported: yes
    Active: no

 sudo turbostat 
turbostat version 21.05.04 - Len Brown <lenb@kernel.org>
CPUID(0): AuthenticAMD 0x10 CPUID levels
CPUID(1): family:model:stepping 0x17:60:1 (23:96:1) microcode 0x0
CPUID(0x80000000): max_extended_levels: 0x80000020
CPUID(1): SSE3 MONITOR - - - TSC MSR - HT -
CPUID(6): APERF, No-TURBO, No-DTS, No-PTM, No-HWP, No-HWPnotify, No-HWPwindow, No-HWPepp, No-HWPpkg, No-EPB
CPUID(7): No-SGX
RAPL: 234 sec. Joule Counter Range, at 280 Watts
/dev/cpu_dma_latency: 2000000000 usec (default)
current_driver: acpi_idle
current_governor: menu
current_governor_ro: menu
cpu6: POLL: CPUIDLE CORE POLL IDLE
cpu6: C1: ACPI FFH MWAIT 0x0
cpu6: C2: ACPI IOPORT 0x414
cpu6: C3: ACPI IOPORT 0x415
NSFOD /sys/devices/system/cpu/cpu6/cpufreq/scaling_driver
cpu0: MSR_RAPL_PWR_UNIT: 0x000a1003 (0.125000 Watts, 0.000015 Joules, 0.000977 sec.)
Core	CPU	Avg_MHz	Busy%	Bzy_MHz	TSC_MHz	IPC	IRQ	POLL	C1	C2	C3	POLL%	C1%	C2%	C3%	CorWatt	PkgWatt
-	-	15	0.72	2053	1797	1.01	2799	1	507	252	1622	0.00	0.36	0.73	98.22	0.08	0.31
0	0	6	0.39	1606	1797	0.26	368	0	42	6	317	0.00	0.23	0.11	99.33	0.00	0.31
0	1	4	0.23	1658	1797	0.20	180	0	29	41	116	0.00	0.30	7.71	91.79
1	2	75	3.15	2380	1797	1.38	263	1	59	29	40	0.00	0.62	0.54	95.70	0.03
1	3	5	0.32	1602	1797	0.58	78	0	12	11	41	0.00	0.14	0.22	99.34
2	4	9	0.42	2030	1797	0.38	99	0	10	7	64	0.00	0.14	0.14	99.31	0.00
2	5	7	0.36	2028	1797	0.30	73	0	4	10	35	0.00	0.06	0.20	99.39
3	6	2	0.11	1588	1797	0.24	79	0	17	16	41	0.00	0.30	0.30	99.30	0.00
3	7	2	0.12	1676	1797	0.22	96	0	7	7	76	0.00	0.13	0.14	99.62
4	8	11	0.71	1563	1797	1.23	161	0	15	7	105	0.00	0.15	0.13	99.03	0.00
4	9	4	0.24	1559	1797	0.29	141	0	56	51	29	0.00	0.83	0.97	97.98
5	10	2	0.14	1426	1797	0.24	105	0	18	9	76	0.00	0.18	0.14	99.56	0.00
5	11	3	0.21	1397	1797	0.53	133	0	68	14	55	0.00	0.95	0.26	98.60
6	12	28	1.37	2076	1797	1.12	174	0	26	6	76	0.00	0.32	0.12	98.22	0.01
6	13	14	0.83	1735	1797	0.23	159	0	46	4	96	0.00	0.34	0.08	98.78
7	14	55	2.30	2384	1797	1.26	265	0	78	32	62	0.00	0.82	0.57	96.35	0.02
7	15	9	0.59	1500	1797	0.22	425	0	20	2	393	0.00	0.20	0.04	99.30

cat  /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver 
cat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver: No such file or directory

Should I insert back acpi_cpufreq?

jonathon · June 4, 2022, 1:35pm

IMG_20220604_143206_DRO

Works here - CPPC settings are available using the universal browser thingy.

pebcak · June 4, 2022, 1:41pm

Thanks for following up @jonathon!

That looks really promising!

I’ll have a read at the link you posted and hopefully I might be able to try it later this evening.

Dougie · June 4, 2022, 3:39pm

I had no idea this existed! I wasn’t able to turn on CPPC (Lenovo Flex14-API) but I was able to:

Undervolt the CPU
Switch the power mode from the stock 15-25w mode to 35w mode (45 and even 54w modes exist but scare me, considering this is a very thin device lol)
Actually allow the RAM to run at it’s rated clock speed instead of a locked lower frequency
Turn PCI-E power mode from “power save” to balanced or performance which increased my WiFi download speed from ~260mbps to ~480mbps

Very neat tool

ricklinux · June 4, 2022, 4:00pm

I haven’t been able to get it to work on my HP laptop either with Ryzen 4700U

Edit: I don’t think it works on my lenovo either. It’s strange because i do see cppc in the output as a flag.

Echoa · June 4, 2022, 5:04pm

Ifwe can get more confirmation about it I’ll add to the OP that certain lenovo and HP systems that “should” support it don’t due to current BIOS limitations.

That lenovo thread looks good, does this apply to many systems from lenovo that generation?