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author | Ulf Hansson <ulf.hansson@linaro.org> | 2016-10-13 16:58:54 +0200 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-11-19 00:15:39 +0100 |
commit | 1d9174fbc55ec99ccbfcafa3de2528ef78a849aa (patch) | |
tree | 7554f95445c5a71a76fd4a044e8a595b94471e89 /drivers/base/power | |
parent | a8636c89648ab12e59d8f3aa667ec76fc96fd643 (diff) | |
download | blackbird-op-linux-1d9174fbc55ec99ccbfcafa3de2528ef78a849aa.tar.gz blackbird-op-linux-1d9174fbc55ec99ccbfcafa3de2528ef78a849aa.zip |
PM / Runtime: Defer resuming of the device in pm_runtime_force_resume()
When the pm_runtime_force_suspend|resume() helpers were invented, we still
had CONFIG_PM_RUNTIME and CONFIG_PM_SLEEP as separate Kconfig options.
To make sure these helpers worked for all combinations and without
introducing too much of complexity, the device was always resumed in
pm_runtime_force_resume().
More precisely, when CONFIG_PM_SLEEP was set and CONFIG_PM_RUNTIME was
unset, we needed to resume the device as the subsystem/driver couldn't
rely on using runtime PM to do it.
As the CONFIG_PM_RUNTIME option was merged into CONFIG_PM a while ago, it
removed this combination, of using CONFIG_PM_SLEEP without the earlier
CONFIG_PM_RUNTIME.
For this reason we can now rely on the subsystem/driver to use runtime PM
to resume the device, instead of forcing that to be done in all cases. In
other words, let's defer the runtime resume to a later point when it's
actually needed.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base/power')
-rw-r--r-- | drivers/base/power/runtime.c | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 60ebb04d8140..f0d863089345 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1489,6 +1489,16 @@ int pm_runtime_force_suspend(struct device *dev) if (ret) goto err; + /* + * Increase the runtime PM usage count for the device's parent, in case + * when we find the device being used when system suspend was invoked. + * This informs pm_runtime_force_resume() to resume the parent + * immediately, which is needed to be able to resume its children, + * when not deferring the resume to be managed via runtime PM. + */ + if (dev->parent && atomic_read(&dev->power.usage_count) > 1) + pm_runtime_get_noresume(dev->parent); + pm_runtime_set_suspended(dev); return 0; err: @@ -1498,16 +1508,20 @@ err: EXPORT_SYMBOL_GPL(pm_runtime_force_suspend); /** - * pm_runtime_force_resume - Force a device into resume state. + * pm_runtime_force_resume - Force a device into resume state if needed. * @dev: Device to resume. * * Prior invoking this function we expect the user to have brought the device * into low power state by a call to pm_runtime_force_suspend(). Here we reverse - * those actions and brings the device into full power. We update the runtime PM - * status and re-enables runtime PM. + * those actions and brings the device into full power, if it is expected to be + * used on system resume. To distinguish that, we check whether the runtime PM + * usage count is greater than 1 (the PM core increases the usage count in the + * system PM prepare phase), as that indicates a real user (such as a subsystem, + * driver, userspace, etc.) is using it. If that is the case, the device is + * expected to be used on system resume as well, so then we resume it. In the + * other case, we defer the resume to be managed via runtime PM. * - * Typically this function may be invoked from a system resume callback to make - * sure the device is put into full power state. + * Typically this function may be invoked from a system resume callback. */ int pm_runtime_force_resume(struct device *dev) { @@ -1524,6 +1538,17 @@ int pm_runtime_force_resume(struct device *dev) if (!pm_runtime_status_suspended(dev)) goto out; + /* + * Decrease the parent's runtime PM usage count, if we increased it + * during system suspend in pm_runtime_force_suspend(). + */ + if (atomic_read(&dev->power.usage_count) > 1) { + if (dev->parent) + pm_runtime_put_noidle(dev->parent); + } else { + goto out; + } + ret = pm_runtime_set_active(dev); if (ret) goto out; |