Messages in this thread | | | Date | Tue, 9 Apr 2024 17:46:15 +0200 | From | Johan Hovold <> | Subject | Re: [PATCH v2] HID: i2c-hid: wait for i2c touchpad deep-sleep to power-up transition |
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On Tue, Apr 09, 2024 at 12:53:43PM +0200, Łukasz Majczak wrote:
> > Can you please explain why this would not a problem for all future > > transactions as well?
> The problem is that the probe function calling i2c_smbus_read_byte() > is not aware that > uC on the other end is in a deep sleep state so the first read will > fail and so the whole probe. > > In a normal scenario, when a user touches the touchpad (when it is in > a deep sleep), the touch will first wake up the uC and > then generate an interrupt to AP, so in this case the touchpad is > fully awake and operational.
Sure, but what about other transactions that are initiated by the host (e.g. SET_POWER)?
Perhaps this hack at probe is enough for your use case, but is an incomplete hack and at a minimum you'd need to add a comment explaining why it is there.
Johan
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