On Thursday, October 26, 2017 10:41:40 PM CEST Wolfram Sang wrote: > On Mon, Oct 16, 2017 at 03:31:17AM +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > 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@xxxxxxxxx> > > So, if the designware maintainers ack it, I will, too. Thanks! I need to post a new revision of the core patches, so I'll send this one again later. Likely during the next cycle. Thanks, Rafael
