# Power Mode and Fan Control ### Problem No fan and power mode control is available is available for Linux or Windows on Sixunited's AXB35 board. ### Solution for Linux There is a [ec-su_axb35-linux kernel module](https://github.com/cmetz/ec-su_axb35-linux) written by Christoph Metz. It allows you to: - read current fan speeds and modes - switch modes of each of the three available fans - control fan speed in `fixed` mode - control fan speed with custom curves in `curve` mode - read current power mode - change current power mode - read current APU temperature #### Generic Installation 1. Install module building dependencies (depends on your distro, on debian/ubuntu install `build-essential` and `linux-headers-$(uname -r)` packages). 2. Clone the repo with `git clone https://github.com/cmetz/ec-su_axb35-linux.git`. 3. Build and install the module with `cd ec-su_axb35-linux && sudo make install`. 4. Try loading the module with `modprobe ec_su_axb35` and check your `dmesg` afterwards. You should see the `Sixunited AXB35-02 EC driver loaded` message. 5. Run `scripts/info.sh` and check that all information is there. 6. Run `scripts/test_fan_mode_fixed.sh`, it should test your fans on all 6 fixed levels. 7. If everything is good, you can make the module automatically load on system boot with `sudo echo ec_su_axb35 >> /etc/modules`. If it says "permission denied", drop into root console with `su` or `sudo su -` and try again. #### Usage Reading and writing all of the parameters happens through sysfs with `/sys/class/ec_su_axb35` path. You can find detailed information in [the repo's readme file](https://github.com/cmetz/ec-su_axb35-linux/blob/main/README.md). Some examples: - `cat /sys/class/ec_su_axb35/fan2/rpm` to get current rpm of fan2 - `echo fixed > /sys/class/ec_su_axb35/fan3/mode && echo 2 > /sys/class/ec_su_axb35/fan3/level` to switch fan3 to fixed mode and set speed to level 2 - `echo balanced > /sys/class/ec_su_axb35/apu/power_mode` to set power mode to balanced (85W) You can also call `su_axb35_monitor` anywhere to monitor all available values in realtime:  To apply specific settings at system startup, place them in your `rc.local` file or utilize any other methods for executing commands during boot, such as creating a systemd unit. In the future, these parameters will also be configurable through module options. #### Custom Curves The custom curves define temperature thresholds for fan power levels: - **Ramp-up curve** (`/sys/class/ec_su_axb35/fanX/rampup_curve`): temperature points where fan increases to the next level - **Ramp-down curve** (`/sys/class/ec_su_axb35/fanX/rampdown_curve`): temperature points where fan decreases to the previous level For example, with these settings: - `rampup_curve = 60,70,83,95,97` - `rampdown_curve = 40,50,80,94,96` **When CPU is heating up:** - Below 60°: Fan at level 0 (minimum) - At 60°: Increases to level 1 - At 70°: Increases to level 2 - At 83°: Increases to level 3 - At 95°: Increases to level 4 - At 97°: Increases to level 5 (maximum) **When CPU is cooling down:** - Above 96°: Fan stays at level 5 - Below 96°: Decreases to level 4 - Below 94°: Decreases to level 3 - Below 80°: Decreases to level 2 - Below 50°: Decreases to level 1 - Below 40°: Decreases to level 0 This creates a buffer at each level that prevents the fan from rapidly switching between speeds when temperature fluctuates around threshold values. Curves are being applied only when `curve` mode is set on a specific fan, each fan has their own curves. ### Solution for Windows Based on the research made for the Linux module [a Windows implementation has been written as well](https://github.com/deseven/ec-su_axb35-win). The only major limitation is the need to disable Secure Boot, everything else should be pretty simple, just follow the readme in the repo. ### Fine-tuning Power Limits If you want more gradual control over power modes, there's a [RyzenAdj](https://github.com/FlyGoat/RyzenAdj) utility (or [UXTU](https://amdaputuningutility.com) for Windows). Main 3 parameters we are interested in are: - `STAPM LIMIT` (sustained power draw) - `PPT LIMIT FAST` (boost power draw) - `PPT LIMIT SLOW` (average power draw) Default values on all 3 selectable power modes (use `ryzenadj --info` to read them): | Power Mode | STAPM LIMIT | PPT LIMIT FAST | PPT LIMIT SLOW | | ----------- | ----------- | -------------- | -------------- | | Quiet | 54.0 | 100.0 | 54.0 | | Balanced | 85.0 | 120.0 | 120.0 | | Performance | 120.0 | 140.0 | 120.0 | Example on setting the power limit to static 100W with no boost: `ryzenadj --stapm-limit=100000 --fast-limit=100000 --slow-limit=100000` **Note that changing the power mode via the EC controller (using `ec-su_axb35-linux` or otherwise) resets these values to their defaults.** ### Relevant Pages - [[Guides/Hardware-Monitoring]] - [[Guides/Power-Modes-and-Performance]]