Re: New Lenovo Legion Fan, Temperature, Power Mode Driver

[Hans de Goede <hdegoede@redhat.com>]

Hi John,

On 1/10/23 14:26, John Martens wrote:
> Dear Kernel devs, Mr. Hans de Goede, Mr. Ike Panhc,
> 
> I am currently working on a driver for fan control, fan speed, temperature sensors, and power mode (platform profile) for Lenovo Legion Laptops. Switching iGPU/dGPU could also be possible. It is a port of the closed and open tools in Windows LenovoLegionToolkit, Vantage, LegionFanControl. I am testing it on different laptops with the help of a forum/chat and its working quite good.

Thank you for reaching out. I'm currently catching up with
quite a big patch/bug backlog after being on holiday for
2 weeks. I'll get back to you on this, but please give
me some time.

If you have not heard back from me in 2 weeks, feel free
to ping me about this.

Regards,

Hans

 


> 
> There is a README (https://github.com/johnfanv2/LenovoLegionLinux) and code (https://github.com/johnfanv2/LenovoLegionLinux/blob/main/kernel_module/legion-laptop.c).
> 
> I would be interested to get your opinion.
> 
> Questions
> 
> Should this extend ideapad_laptop.c or a new file?
>     - pro:
>         - both access parts of the same hardware
>     - con:
>         - both files are already quite large
>         - it only works on Lenovo Legion laptops that have this 
>           custom control firmware in the embedded controller (EC)
>         - there is almost no reuse of code
> 
> Which method do you prefer writing to EC memory for older models? With ioremap or outb? 
>     - To use ioremap one needs to get the start address. It is
>       different on Intel vs AMD. It is the same as a OperationRegion
>       in the ACPI tables, e.g. "OperationRegion (ERAX, SystemMemory,  
>       0xFE00D400, 0xFF)". However, I have found no kernel functions  
>       to get the address (here 0xFE00D400) of a  OperationRegion.  
>       One could also hardcode it for each model/firmware.
>     - alternative (which I am currently using) is sending commands    
>       to IO ports 0x4E/0x4F (Super IO controller). 
> 
> Background
> 
> The laptops come with an embedded controller (EC) from ITE. These usually come with a 3 point fan curve in ROM, but also can be flashed with a small additional custom program. Lenovo implemented implemented a 10 point fan curve. The program is also shipped with each EFI update.
> 
> The fan curve can be edited by writing to some memory locations in the EC. These locations are
> 
> The driver works by:
> - directly writing/reading embedded controller memory
>     - older models (2020-2021): there are two possibilities
>         - the EC memory is already memory mapped, so one can 
>           use ioremap
>         - one can use outb/inb and write sequenc of commands to 
>           port 0x43, 0x4F (super IO ports)
>         - ideapad_laptop.c writes to some parts of EC memory 
>           with ACPI methods VPCR, VPCW. However, these do not seem  
>           to work in the memory region with the fan curve.
>     - newer models (2022): these provide ACPI/WMI methods  
>       setFanCurve/getFanCurve to write to these regions. However, I  
>       have implemented that and have no models for testing
> 
> The driver works for the models 2020-2022. The code layout is heavily inspired by the ideapad_laptop driver.
> 
> Best regards,
> 
> John Martens
>