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2025-07-08 21:12:40 deseven: new guide| /dev/null .. Guides/Power-Mode-and-Fan-Control.md | |
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| + | # Power Mode and Fan Control |
| + | |
| + | ### Problem |
| + | No fan and power mode control is available in Linux. |
| + | |
| + | ### Solution |
| + | 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 should be `build-essential` and `linux-headers` 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 && 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 `echo ec_su_axb35 >> /etc/modules`. |
| + | |
| + | #### 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/rampup_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. |
| + | |
| + | ### Relevant Pages |
| + | [[Guides/Hardware-Monitoring]] |