[SOLVED] AMD 4500U (GB-BRR5H-4500) and pstates

[lagalopex]

Hello,

I have some mini pc with an AMD 4500U and of course put gentoo on it.
Kernel 6.1.16-gentoo is compiled with CONFIG_X86_AMD_PSTATE=y and booted with amd_pstate=passive.
lscpu mentiones cppc, but always only the acpi-cpufreq is used. (That one is working, but only supplies three steps, with the lowest being 1.4 GHz.)

1. To my understanding pstates should be support by this APU, right?
1.1 Does anyone have working pstates on a 4500U?

I get the following dmesg:
amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

The newest bios is installed, AMI 2.20.1275, for GB-BRR5H-4500 Ver F09.
I cannot find any entry in the BIOS with a name like CP(P)C.

2. Does it have other names?

3. Anything else I can do/try?

[RayDude]

I just set this up. Did you also add: 'initcall_blacklist=acpi_cpufreq_init' to your grub default command line?

You'll also need to see if it's enabled in BIOS. Laptop BIOSes are not the most friendly. There is usually a power setting which needs to be enabled. I would expect setting bios defaults should enable it, since it's a laptop.

Hello,

I have some mini pc with an AMD 4500U and of course put gentoo on it.
Kernel 6.1.16-gentoo is compiled with CONFIG_X86_AMD_PSTATE=y and booted with amd_pstate=passive.
lscpu mentiones cppc, but always only the acpi-cpufreq is used. (That one is working, but only supplies three steps, with the lowest being 1.4 GHz.)

1. To my understanding pstates should be support by this APU, right?
1.1 Does anyone have working pstates on a 4500U?

I get the following dmesg:
amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

The newest bios is installed, AMI 2.20.1275, for GB-BRR5H-4500 Ver F09.
I cannot find any entry in the BIOS with a name like CP(P)C.

2. Does it have other names?

3. Anything else I can do/try?

[RayDude]

Well. I'm in the same boat with my work laptop.

[ 0.512882] amd_pstate: the _CPC object is not present in SBIOS or ACPI disabled

I'll work on this a bit later. Let me know if you find anything.

Works fine on my server which is Zen3.

[RayDude]

I still haven't gotten it working, but here's a useful thread: https://forum.endeavouros.com/t/how-to- ... /83?page=5

[RayDude]

I got it working.

In that thread is a link to a bootable bios which you can boot on an AMD system to control features that the BIOS may not give you control of.

All options are there. BE CAREFUL!

CPPC is listed in SMU_OPTIONS (it's a bit difficult to find).

Once you force it to enabled, the p_state driver will load.

By the way, this only affects 4X00 series laptops. 5X00 and 6X00 laptops should have this enabled by default.

[lagalopex]

I just set this up. Did you also add: 'initcall_blacklist=acpi_cpufreq_init' to your grub default command line?

No, I never read that this is needed.

You'll also need to see if it's enabled in BIOS. Laptop BIOSes are not the most friendly. There is usually a power setting which needs to be enabled. I would expect setting bios defaults should enable it, since it's a laptop.

This is a mini pc. But I have not found anything, I already enabled everything power management related.

Works fine on my server which is Zen3.

For me, too, the Zen3 works like a charm @400MHz.

In that thread is a link to a bootable bios which you can boot on an AMD system to control features that the BIOS may not give you control of.
CPPC is listed in SMU_OPTIONS (it's a bit difficult to find).

No luck for me. I tried it, but everytime I try to enter the CPU setting I am back in the boot menu (where I selected the thumb drive).
(I tried every path and quite some fail like that. Do you have the full path for that option?)

[RayDude]

I just set this up. Did you also add: 'initcall_blacklist=acpi_cpufreq_init' to your grub default command line?

No, I never read that this is needed.

You'll also need to see if it's enabled in BIOS. Laptop BIOSes are not the most friendly. There is usually a power setting which needs to be enabled. I would expect setting bios defaults should enable it, since it's a laptop.

This is a mini pc. But I have not found anything, I already enabled everything power management related.

Works fine on my server which is Zen3.

For me, too, the Zen3 works like a charm @400MHz.

In that thread is a link to a bootable bios which you can boot on an AMD system to control features that the BIOS may not give you control of.
CPPC is listed in SMU_OPTIONS (it's a bit difficult to find).

No luck for me. I tried it, but everytime I try to enter the CPU setting I am back in the boot menu (where I selected the thumb drive).
(I tried every path and quite some fail like that. Do you have the full path for that option?)

To install and boot that image, you should format your usb drive as FAT-32.

Unzip UniversalAMDFormBrowser.zip to a new directory on your local drive.

Then mount the USB drive and copy $(cp -R /whereyouunzippedthefiles/* /mnt/usbkey) all the files from UniversalAMDFormBrowser.zip onto the root of the FAT-32 drive.

When you boot your mini computer press F12 over and over and hopefully a boot menu will show up. If it doesn't, then you need to enter bios and find the boot menu on it and enable booting from the USB Key.

Choose the USB drive with UniversalAMDFormBrowser installed and it should boot into a BIOS like setup environment.

From there, the menu system is a bit complicated. As I remember it's one of the top menus, then a center menu to get to SMU_OPTIONS. Once you see it, you'll know it. The CPPC is listed on that page, you just force it to enable from AUTO because AUTO disables it.

Save the settings, reboot and it should work.

It took me at least five minutes to find CPPC.

Remember: don't change anything else. That tool is powerful enough to allow you to brick your own PC.

[lagalopex]

From there, the menu system is a bit complicated. As I remember it's one of the top menus, then a center menu to get to SMU_OPTIONS. Once you see it, you'll know it. The CPPC is listed on that page, you just force it to enable from AUTO because AUTO disables it.

That path was the question.
I already got it starting and could navigate in that "bios like enviroment", but quite some menu entries in there just make it quit. Then I am back in the boot menu where I selected the thumbdrive with the UniversalAMDFormBrowser.
The most promising one was something like "CPU Options" in one of the "AMD XXX" sections, but it quits.

[RayDude]

It sounds like the boot drive you made is not working. Can you confirm you formatted the USB drive as FAT32? Then unzipped the BIOS editor program and cp -R the files from the zip folder to the root directory of the FAT32 USB drive?

I couldn't run it on my work laptop. I have a million important windows open.

I ran it on my 6800H personal laptop and found SMU Options on it, however CPPC was not listed there.

If this doesn't help, I'll reboot my work laptop this weekend and find the exact path.

Device Manager -> AMD CBS -> SMU Common Options

Let me know how it goes.

[lagalopex]

It sounds like the boot drive you made is not working. Can you confirm you formatted the USB drive as FAT32? Then unzipped the BIOS editor program and cp -R the files from the zip folder to the root directory of the FAT32 USB drive?

Booting the drive worked, as I was able to enter that UniversalAMDFormBrowser.
But retried it with another thumbdrive... same result.

Device Manager -> AMD CBS -> SMU Common Options

I dont have that path.
In "Device Manager -> AMD CBS" I have:
CPU Common Options (causes that quit of the UniversalAMDFormBrowser and I am back to the boot menu, where I have to select the thumbdrive again.)
DF Common Options
UMC Common Options
NBIO Common Options
FCH Common Options
Soc Miscellaneous Control

I checked all the other entries, but non contained some SMU or CPPC option.

[RayDude]

It sounds like the boot drive you made is not working. Can you confirm you formatted the USB drive as FAT32? Then unzipped the BIOS editor program and cp -R the files from the zip folder to the root directory of the FAT32 USB drive?

Booting the drive worked, as I was able to enter that UniversalAMDFormBrowser.
But retried it with another thumbdrive... same result.

Device Manager -> AMD CBS -> SMU Common Options

I dont have that path.
In "Device Manager -> AMD CBS" I have:
CPU Common Options (causes that quit of the UniversalAMDFormBrowser and I am back to the boot menu, where I have to select the thumbdrive again.)
DF Common Options
UMC Common Options
NBIO Common Options
FCH Common Options
Soc Miscellaneous Control

I checked all the other entries, but non contained some SMU or CPPC option.

Are you running the latest BIOS on that mini computer?

At the end of the work day today, I'll reboot my work laptop and document the exact path where I found SMU Options.

[RayDude]

Here is the path for my 4800H laptop:

Device Manager

AMD CBS

NBIO Common Options

SMU Common Options

CPPC

Hope this works out for you.

[lagalopex]

Are you running the latest BIOS on that mini computer?

Yes, that was my first attempt.

Device Manager > AMD CBS > NBIO Common Options > SMU Common Options > CPPC

I tried again today. No matter how I booted, the setting always cause the menu to quit.

But I finally got it working when I first entered the UEFI shell and executed the uiapp from there. (Actually it looked like the real bios and not like the simple one when I booted...)
The option was there, I could enable it and now the driver loads and let the system reduce the clock as low as 400 MHz as well!

Thank you!

[RayDude]

Glad it worked out!