| Message ID | 1780798.HpLBO7aPyI@aspire.rjw.lan (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On 01/03/2018 02:35 AM, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > Modify i2c-designware-platdrv to set DPM_FLAG_SMART_PREPARE for its > devices and return 0 from the system suspend ->prepare callback > if the device has an ACPI companion object in order to tell the PM > core and middle layers to avoid skipping system suspend/resume > callbacks for the device in that case (which may be problematic, > because the device may be accessed during suspend and resume of > other devices via I2C operation regions then). > > Also the pm_runtime_suspended() check in dw_i2c_plat_prepare() > is not necessary any more, because the core does it when setting > power.direct_complete for the device, so drop it. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/i2c/busses/i2c-designware-platdrv.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
On Mon, Jan 08, 2018 at 04:31:49PM +0200, Jarkko Nikula wrote: > On 01/03/2018 02:35 AM, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > Modify i2c-designware-platdrv to set DPM_FLAG_SMART_PREPARE for its > > devices and return 0 from the system suspend ->prepare callback > > if the device has an ACPI companion object in order to tell the PM > > core and middle layers to avoid skipping system suspend/resume > > callbacks for the device in that case (which may be problematic, > > because the device may be accessed during suspend and resume of > > other devices via I2C operation regions then). > > > > Also the pm_runtime_suspended() check in dw_i2c_plat_prepare() > > is not necessary any more, because the core does it when setting > > power.direct_complete for the device, so drop it. > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > --- > > drivers/i2c/busses/i2c-designware-platdrv.c | 10 +++++++++- > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Acked-by: Wolfram Sang <wsa@the-dreams.de>
Index: linux-pm/drivers/i2c/busses/i2c-designware-platdrv.c =================================================================== --- linux-pm.orig/drivers/i2c/busses/i2c-designware-platdrv.c +++ linux-pm/drivers/i2c/busses/i2c-designware-platdrv.c @@ -372,6 +372,8 @@ static int dw_i2c_plat_probe(struct plat ACPI_COMPANION_SET(&adap->dev, ACPI_COMPANION(&pdev->dev)); adap->dev.of_node = pdev->dev.of_node; + dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_SMART_PREPARE); + /* The code below assumes runtime PM to be disabled. */ WARN_ON(pm_runtime_enabled(&pdev->dev)); @@ -435,7 +437,13 @@ MODULE_DEVICE_TABLE(of, dw_i2c_of_match) #ifdef CONFIG_PM_SLEEP static int dw_i2c_plat_prepare(struct device *dev) { - return pm_runtime_suspended(dev); + /* + * If the ACPI companion device object is present for this device, it + * may be accessed during suspend and resume of other devices via I2C + * operation regions, so tell the PM core and middle layers to avoid + * skipping system suspend/resume callbacks for it in that case. + */ + return !has_acpi_companion(dev); } static void dw_i2c_plat_complete(struct device *dev)