[SRU][K/Unstable][PATCH 0/1] Compile SiFive PWM driver as a module

[Emil Renner Berthing]

[ Impact ]

 * When adding earlycon to the kernel command line on the
   SiFive Unmatched board the serial console will print garbage
   halfway through booting until entering userspace and other
   other drivers are loaded.

 * The problem is the UART driver doesn't claim its clocks
   properly so the PWM driver will turn off the parent clock
   until PWM is needed for the LEDs on the board.

 * Compiling the PWM driver as a module so it will be loaded
   at the same time the LED drivers are loaded is a workaround
   until the following patch is backported
   643792048ee8 ("serial: sifive: enable clocks for UART when probed")

 * Only the SoCs on the SiFive Unleashed and Unmatched boards use
   this PWM driver, but none of them need it at boot time, so should
   be harmless.

[ Test Plan ]

 * Add earlycon and watch the serial console while booting.

 * Test that PWM leds still work after the PWM driver module is loaded.

[ Where problems could occur ]

 * There might be a hidden dependency on loading the PWM driver early.

Emil Renner Berthing (1):
  UBUNTU: [Config] Set CONFIG_PWM_SIFIVE=m for riscv64

 debian.master/config/annotations          | 2 +-
 debian.master/config/config.common.ubuntu | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.37.2