Messages in this thread |  | | Subject | Re: [PATCH 6/7] PM: i2c-designware-platdrv: Optimize power management | From | Jarkko Nikula <> | Date | Mon, 8 Jan 2018 16:31:58 +0200 |
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On 01/03/2018 02:37 AM, 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 ACPI PM domain and 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 causes the device's runtime PM status to be set 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 resume for the device if platform firmware > has been involved in resuming the system, so make it call > pm_resume_via_firmware() to check that. Also make it check the > runtime PM status of the device instead of its direct_complete > flag which also works if the device remained suspended due to > the DPM_FLAG_LEAVE_SUSPENDED driver flag. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/i2c/busses/i2c-designware-core.h | 2 - > drivers/i2c/busses/i2c-designware-platdrv.c | 31 ++++++++++------------------ > 2 files changed, 12 insertions(+), 21 deletions(-) > This doesn't apply to linux-next due 0326f9f801b2 ("i2c: designware: rename i2c_dw_plat_prepare_clk to i2c_dw_prepare_clk"). It was trivial to fix which I did locally for testing.
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
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