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

[Tim Gardner]

On 10/10/22 04:46, Emil Renner Berthing wrote:
> [ 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(-)
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>
-- 
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Tim Gardner
Canonical, Inc