[RFC PATCH 0/1] Ensure safe fan state during restart

[florin . leotescu]

From: Florin Leotescu <florin.leotescu@xxxxxxx>

Hi,

The EMC2305 fan controller retains the last PWM duty cycle programmed
by the kernel until it is reconfigured by another software stage.

During a soft reboot, if the system remains powered while the restart
handoff occurs, the controller may continue driving the fans with the
previously programmed duty cycle. On systems where no later stage
reconfigures the controller promptly, this may leave the fans running
below a desired fail-safe level.

This RFC proposes setting all fan channels to maximum PWM duty cycle
during the driver's shutdown callback so that the controller is left in
a safe cooling state before the restart handoff.

Feedback is welcome on whether this behaviour is appropriate for the
driver or if it should instead be controlled through a platform-specific
mechanism.

Florin Leotescu (1):
  hwmon: emc2305: Set max PWM state during shutdown

 drivers/hwmon/emc2305.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

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2.34.1