According to the mailing list, Linux 5.13 will allow Lenovo to control the second fan on its ThinkPad X1 Carbon Gen 9. This patch comes from an independent user and enables the ThinkPad ACPI driver to control the second fan of the latest ThinkPad X1 Carbon laptop to prevent the secondary fan from running at a constant speed forever.
The ThinkPad ACPI driver has supported the second fan for some time, and it has been enabled for related Lenovo laptops with additional fans, but each device needs to be whitelisted through the quirk table based on ACPI information.
Currently, this new feature has been submitted along with other platform-drivers-x86 fixes and then merged into the Linux 5.13 mainline. However, currently, only ThinkPad X1 Carbon Gen 9 supports this feature. ThinkPad X1 Carbon Gen9 is now not only a good Tiger Lake laptop from a hardware point of view, but also has good Linux support. It can be seen that Lenovo has made more and more contributions to Linux.