On Sat, Sep 08, 2018 at 08:29:59PM +0200, Hans de Goede wrote:
> After recent kernel changes Bay and Cherry Trail devices where the I2C bus
> to the PMIC is shared with PUNIT properly reach S0ix states when suspended.
>
> As explained in detail in the commit message of commit 9d9a152ebaa8 ("i2c:
> designware: Re-init controllers with pm_disabled set on resume"), the
> I2C controller for this bus has an effectively empty _PS3 ACPI method and
> thus is left in D0 during suspend. It seems to somehow automatically
> powerdown once S0i3 is reached, which means that it needs to be
> reinitialized on resume for us to be able to use it again.
>
> The referred commit adds the necessary code to re-init the controller
> to the drivers resume_early method. It turns out that for some devices
> this is too late. On a Peaq C1010 2-in-1 tablet/laptop doing the re-init
> from resume_early leads to the device rebooting on resume.
>
> This commit moves the re-init to resume_noirq, fixing this. Note this
> means that the controller re-init now happens before the early_resume
> handler from drivers/acpi/acpi_lpss.c runs. Which means that the
> controller was not put in D0 yet when we re-init, this is not a problem
> since the controller was never put in D3 in the first place.
>
> This has been tested on the Peaq C1010 and one other Bay Trail device and
> Cherry Trail device, both of which have an I2C bus shared with the PUNIT
> too.
>
> Fixes: 9d9a152ebaa8 ("i2c: designware: Re-init controllers with ...")
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
