Re: [PATCH 1/1] usb: dwc3: qcom: Keep wakeup option default off

[sashiko-bot@kernel.org]

> The "wakeup-source" property, as described in
> Documentation/devicetree/bindings/power/wakeup-source.txt, only says
> that a device is capable of waking up the system. Whether wakeup is
> actually enabled is a policy decision, and drivers use
> device_may_wakeup() to decide whether to arm the hardware wakeup logic.
> 
> Currently dwc3-qcom calls device_init_wakeup(dev, true) when the
> property is present, so USB wakeup is enabled by default. Users who do
> not want USB activity (e.g. connect/disconnect) to wake up the system
> have to disable it through power/wakeup, otherwise unexpected wakeups
> may happen.
> 
> Having wakeup enabled by default also costs power. In host mode, system
> suspend skips dwc3_core_exit() and keeps the PHYs and the wakeup
> detection logic powered so that the wakeup interrupts can fire, even on
> systems where USB is never used as a wakeup source and the controller
> could be fully powered off.
> 
> Keep the wakeup option default off and only mark the device as wakeup
> capable, so that the user decides which USB controller is used as a
> system wakeup source. Users who need it can enable it with:
> 
>   echo enabled > /sys/devices/.../<dwc3 device>/power/wakeup
> 
> While at it, drop the local wakeup_source variable and use
> device_property_read_bool() like the other property reads in probe.
> 
> Signed-off-by: Peter Chen <peter.chen@oss.qualcomm.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261110092157.2989350-1-peter.chen@oss.qualcomm.com?part=1