From: Douglas Anderson dianders@chromium.org
[ Upstream commit b4060db9251f919506e4d672737c6b8ab9a84701 ]
The PM Runtime docs say:
Drivers in ->remove() callback should undo the runtime PM changes done in ->probe(). Usually this means calling pm_runtime_disable(), pm_runtime_dont_use_autosuspend() etc.
From grepping code, it's clear that many people aren't aware of the need to call pm_runtime_dont_use_autosuspend().
When brainstorming solutions, one idea that came up was to leverage the new-ish devm_pm_runtime_enable() function. The idea here is that:
* When the devm action is called we know that the driver is being removed. It's the perfect time to undo the use_autosuspend.
* The code of pm_runtime_dont_use_autosuspend() already handles the case of being called when autosuspend wasn't enabled.
Suggested-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Douglas Anderson dianders@chromium.org Reviewed-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Stable-dep-of: 3d07a411b4fa ("drm/msm/dsi: Use pm_runtime_resume_and_get to prevent refcnt leaks") Signed-off-by: Amit Pundir amit.pundir@linaro.org --- drivers/base/power/runtime.c | 5 +++++ include/linux/pm_runtime.h | 4 ++++ 2 files changed, 9 insertions(+)
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 5824d41a0b74..6699096ff2fa 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1479,11 +1479,16 @@ EXPORT_SYMBOL_GPL(pm_runtime_enable);
static void pm_runtime_disable_action(void *data) { + pm_runtime_dont_use_autosuspend(data); pm_runtime_disable(data); }
/** * devm_pm_runtime_enable - devres-enabled version of pm_runtime_enable. + * + * NOTE: this will also handle calling pm_runtime_dont_use_autosuspend() for + * you at driver exit time if needed. + * * @dev: Device to handle. */ int devm_pm_runtime_enable(struct device *dev) diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 90eaff8b78fc..7efb10518313 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -542,6 +542,10 @@ static inline void pm_runtime_disable(struct device *dev) * Allow the runtime PM autosuspend mechanism to be used for @dev whenever * requested (or "autosuspend" will be handled as direct runtime-suspend for * it). + * + * NOTE: It's important to undo this with pm_runtime_dont_use_autosuspend() + * at driver exit time unless your driver initially enabled pm_runtime + * with devm_pm_runtime_enable() (which handles it for you). */ static inline void pm_runtime_use_autosuspend(struct device *dev) {