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    SubjectRe: [PATCH 11/12] PM: i2c-designware-platdrv: Optimize power management
    On Mon, Oct 16, 2017 at 03:31:17AM +0200, Rafael J. Wysocki wrote:
    > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    >
    > Optimize the power management in i2c-designware-platdrv by making it
    > set the DPM_FLAG_SMART_SUSPEND and DPM_FLAG_LEAVE_SUSPENDED which
    > allows some code to be dropped from its PM callbacks.
    >
    > First, setting DPM_FLAG_SMART_SUSPEND causes the intel-lpss driver
    > to avoid resuming i2c-designware-platdrv devices in its ->prepare
    > callback, so they can stay in runtime suspend after that point even
    > if the direct-complete feature is not used for them.
    >
    > It also causes the PM core to avoid invoking "late" and "noirq"
    > suspend callbacks for these devices if they are in runtime suspend
    > at the beginning of the "late" phase of device suspend during
    > system suspend. That guarantees dw_i2c_plat_suspend() to be
    > called for a device only if it is not in runtime suspend.
    > Moreover, it also causes the PM core to set the device's runtime
    > PM status to "active" after calling dw_i2c_plat_resume() for
    > it, so the driver doesn't need internal flags to avoid invoking
    > either dw_i2c_plat_suspend() or dw_i2c_plat_resume() twice in
    > a row.
    >
    > Second, setting DPM_FLAG_LEAVE_SUSPENDED enables the optimization
    > allowing the device to stay suspended after system resume under
    > suitable conditions, so again the driver doesn't need to take
    > care of that by itself.
    >
    > Accordingly, the internal "suspended" and "skip_resume" flags
    > used by the driver are not necessary any more, so drop them and
    > simplify the driver's PM callbacks.
    >
    > Additionally, notice that dw_i2c_plat_complete() only needs
    > to schedule runtime PM for the device if platform firmware
    > has been involved in resuming the system, so make it call
    > pm_resume_via_firmware() to check that.
    >
    > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

    So, if the designware maintainers ack it, I will, too.

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