Hi,
Indeed, the kernel 5.6 adds support for the IceLake family to the intel_idle driver. However, the intel_idle driver can only find ACPI states, such as C0_ACPI, C1_ACPI, and C3_ACPI on my system.
I took a look at the drivers/idle/intel_idle.c source file of the mainline kernel 5.7.7 and did not find any mention, states table, whatsoever to the IceLake family.
Can you confirm that your idle states are being gathered by the ACPI states table by checking into the idle tab of the powertop utility?
I have a i5-1035g1 on a Lenovo s740 14iil system.
Regards,.