Getting `earlycon` working on AMD platforms is a bit tricky because the uartclk is 48MHz. If the uartclk isn't specified, we default to 115200*16 which results in an incorrect divisor computation. This patch set adds the uartclk to the `console=` documentation, prints a notice to the user that it's using a default uartclk, and implements support for SPCR v3 so that the uartclk can be provided by the firmware. Raul E Rangel (3): Documentation: kernel-parameters: Add uartclk to console=uart earlycon: Print a notice when uartclk is unknown ACPI: SPCR: Add support for rev 3 Documentation/admin-guide/kernel-parameters.txt | 16 ++++++---------- drivers/acpi/spcr.c | 5 ++++- drivers/tty/serial/earlycon.c | 6 +++++- include/acpi/actbl3.h | 6 +++--- 4 files changed, 18 insertions(+), 15 deletions(-) -- 2.46.0.662.g92d0881bb0-goog