I have been running FreeBSD on my HoneyComb and it doesn’t seem to support setting the fan speed yet. Is there a way to set the fans speed from the UEFI firmware? I looked around and didn’t find anything.
Also I read somewhere the additional fan headers aren’t PWM, only the cpu header is PWN. Is that correct? That seemed wrong given its a 4 pin header but I have’t found documents clarifying it.
Currently FreeBSD only supports 2 fan speeds, default and full because there is no Host OS ACPI support for the I2C controllers. I am working on an automatic mode for OS’s that don’t support the I2C bus but haven’t integrated that fully into a release firmware yet.
Yes only the CPU header is connected to the PWM controller.
@jnettlet Can you provide more details on how to control the fan speed?
With the raw OS image I have been using so far the fan keeps running at full speed after boot, which is fine with me (at least once I had replaced the awful fan that came with the board…). However, an interesting side effect of switching from a raw image to a u-boot one is that the fan reduces speed before control is transferred to the OS:
## Booting kernel from Legacy Image at 80200000 ...
Created: 2022-08-03 10:40:09 UTC
Image Type: AArch64 Linux Kernel Image (uncompressed)
Data Size: 16147312 Bytes = 15.4 MiB
Load Address: 80200000
Entry Point: 80200800
Verifying Checksum ... OK
## Flattened Device Tree blob at 80100000
Booting using the fdt blob at 0x80100000
Loading Kernel Image
Loading Device Tree to 000000009fff1000, end 000000009ffff036 ... OK
Releasing fan controller full speed gpio
fsl-mc: DPL not deployed, DPAA2 ethernet not work
While I appreciate the reduced noise, I’m a bit hesitant to do kernel development with the fan not working at full speed (can never tell when something is going to go wrong…).
That is a choose that was made by the BSP team since they can verify that the kernel is built with the appropriate kernel module to manage the PWM controller. Since EDK2 is firmware controlled thermal management I can not guarantee that the host OS knows how to manage the fan so I leave it fully on until the host OS initializes the _TZ ACPI methods. However if you are using Linux rather than BSD then any kernel should have no issues handling the ACPI _TZ methods.
I’m running QNX (the reason I bought this board is to evaluate SMP scalability on a new kernel architecture), so neither BSD nor Linux.
I’m not looking for full control, just a way to keep the fan running at full speed (or restore it to full speed after boot). I’ll gladly RTFM if there is any documentation.
This is all managed by the PWM controller, it is programmable over i2c, or the full fan speed gpio is available. This is all on the schematics and the documentation for the controller is freely available.