Hi all, I received a report from a Surface Laptop 4 which has a UART that is identified as AMDI0022 in ACPI [1] and that does not seem to be supported by the kernel yet. From what I can tell via ACPI, this is similar to the AMDI0020 [2] UART that's already supported by the kernel (well, both are devices with two MMIO regions and an interrupt as far as I can tell...). So it's possible that all that's needed is adding it to the respective device ID lists [3, 4]. Unfortunately, I a) don't have a device to test this myself, b) haven't found any more details on that online, and c) don't want to tell others to test this without knowing a bit more about that (potentially writing random stuff to some unknown MMIO region that I don't know anything about doesn't sound as safe to me as I'd like). Does anyone here have some pointers on what it'd take to support this, or any contacts at AMD that could provide more insight? Regards Max [1]: AMDI0022 in ACPI (Surface Laptop 4) https://github.com/linux-surface/acpidumps/blob/2e24c80d4c7a99a9295aa0b1b2e5e92df93378b4/surface_laptop_4_amd/dsdt.dsl#L1432 [2]: AMDI0020 in ACPI (Surface Laptop 3) https://github.com/linux-surface/acpidumps/blob/62972f0d806cef45ca01341e3cfbabc04c6dd583/surface_laptop_3_15/dsdt.dsl#L1806 [3]: ID list for 8250_dw https://elixir.bootlin.com/linux/v5.12-rc8/source/drivers/tty/serial/8250/8250_dw.c#L715 [4]: ID list for acpi_apd https://elixir.bootlin.com/linux/v5.12-rc8/source/drivers/acpi/acpi_apd.c#L228
