FW16 EC slows the CPU down

[jcdutton]

Device Information

System Model or SKU

[ ] Framework Laptop 16 (AMD Ryzen™ 7040 Series)
No dGPU.

BIOS VERSION

3.0.5

Windows:
N/A

Linux:
Open a terminal and run the following command
sudo dmidecode --string bios-version
03.05

DIY Edition information

Memory: Manufacture and SKU
Kingston Fury Impact: Part Number: KF556S40-32
2x making 64GB total.
Storage: Manufacture and SKU
Model Number: WD_BLACK SN850X 1000GB
Firmware Version: 620361WD

Port/Peripheral information

1. USB-C card, nothing plugged in.
2. Empty
3. Empty
4. Empty
5. USB-C card, FW16 PSU plugged in.
6. USB-A card, nothing plugged in.

Standalone Operation

Are you running your mainboard as a standalone device. Is standalone mode enabled in the BIOS?

• No

Describe the bug

As discovered when I was working on
#41
It is possible for the EC embedded controller to slow the laptop CPU down.
This happens when the EC is busy doing something.
This Issue is a placeholder to try and investigate where the link is between the CPU and the EC. What is causing the slow down? So we can fix it so that the EC cannot slow the CPU down when one does not wish the EC to slow the CPU down.
If anyone can provide ideas of where in the Linux kernel to start looking for the link, it would be helpful.
Some user applications such as "Real Time Audio", "Digital Audio Workstation", "DAW" would benefit as they rely on low latency for audio input, real time processing and output.

Steps To Reproduce

Steps to reproduce the behavior:

1. TBD

Expected behavior

The EC should not slow the CPU down, unless intended to. E.g. Setting "Power Modes" from "Performance" to "Power Saver."

Screenshots

N/A

Operating System (please complete the following information):

• OS/Distribution: Linux/Ubuntu
• Version: 24.04
• Linux Kernel Version: uname -a 6.12.7 <- Mainline compiled kernel.

Additional context

Add any other context about the problem here.

[JohnAZoidberg]

From #41 (comment)

While experimenting, when the EC is busy doing something, it can slow the entire FW laptop down. (to a crawling pace)
Various parts of the EC comms stops working. E.g. detecting power plug/unplug.
I have not diagnosed why EC problems would slow the entire PC down, but will look into it later.
I did not believe the EC could slow the main CPU down until I saw it myself. So it is a possible new source of something to look at if users report slowness. Particularly of interest to Real Time Audio users.

What is it that you are seeing? How do you know the EC is busy doing "something"? Are you looking at the EC console?
What is it doing/printing when you see the slow down?
I assume "to a crawling pace" means that navigating the GUI is slow?

[jcdutton]

I have a EC CCD plugged in so I see the console port output of the EC.
There are a number of things that cause the EC to be busy, e.g. turn up debug out etc. That sort of thing.
I either see too much output on the console port, or the EC hangs and is unresponsive to console port input.
When this is observed, it also tends to slow the CPU down.
This slow down is observed as:

1. Very slow to boot up.
2. Very slow to login
   etc.
   Disabling the EC debug output speeds everything, on the CPU, up again.

I am expecting that there is some IO blocking going on in the Linux kernel, and re-writing the Linux kernel code a bit might resolve the problem.

[ngraham20]

Hey, I've noticed similar symptoms when running a different program. (A game, Albion Online, but I do use fw-fanctrl, which uses EC to apply fan curves) I noticed for me, that it only occurs in "balanced" and "performance" profiles, and switching to "power saver" suddenly makes the system recover. Can you replicate this? Maybe they're the same issue with different triggers?