The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 51888393cc64dd0462d0b96c13ab94873abbc030 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025082129-outdoors-semantic-147a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 51888393cc64dd0462d0b96c13ab94873abbc030 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com Date: Wed, 9 Jul 2025 12:41:45 +0200 Subject: [PATCH] PM: runtime: Take active children into account in pm_runtime_get_if_in_use()
For all practical purposes, there is no difference between the situation in which a given device is not ignoring children and its active child count is nonzero and the situation in which its runtime PM usage counter is nonzero. However, pm_runtime_get_if_in_use() will only increment the device's usage counter and return 1 in the latter case.
For consistency, make it do so in the former case either by adjusting pm_runtime_get_conditional() and update the related kerneldoc comments accordingly.
Fixes: c111566bea7c ("PM: runtime: Add pm_runtime_get_if_active()") Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Reviewed-by: Ulf Hansson ulf.hansson@linaro.org Reviewed-by: Sakari Ailus sakari.ailus@linux.intel.com Cc: 5.10+ stable@vger.kernel.org # 5.10+: c0ef3df8dbae: PM: runtime: Simplify pm_runtime_get_if_active() usage Cc: 5.10+ stable@vger.kernel.org # 5.10+ Link: https://patch.msgid.link/12700973.O9o76ZdvQC@rjwysocki.net
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index c55a7c70bc1a..2ba0dfd1de5a 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1191,10 +1191,12 @@ EXPORT_SYMBOL_GPL(__pm_runtime_resume); * * Return -EINVAL if runtime PM is disabled for @dev. * - * Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either - * @ign_usage_count is %true or the runtime PM usage counter of @dev is not - * zero, increment the usage counter of @dev and return 1. Otherwise, return 0 - * without changing the usage counter. + * Otherwise, if its runtime PM status is %RPM_ACTIVE and (1) @ign_usage_count + * is set, or (2) @dev is not ignoring children and its active child count is + * nonero, or (3) the runtime PM usage counter of @dev is not zero, increment + * the usage counter of @dev and return 1. + * + * Otherwise, return 0 without changing the usage counter. * * If @ign_usage_count is %true, this function can be used to prevent suspending * the device when its runtime PM status is %RPM_ACTIVE. @@ -1216,7 +1218,8 @@ static int pm_runtime_get_conditional(struct device *dev, bool ign_usage_count) retval = -EINVAL; } else if (dev->power.runtime_status != RPM_ACTIVE) { retval = 0; - } else if (ign_usage_count) { + } else if (ign_usage_count || (!dev->power.ignore_children && + atomic_read(&dev->power.child_count) > 0)) { retval = 1; atomic_inc(&dev->power.usage_count); } else { @@ -1249,10 +1252,16 @@ EXPORT_SYMBOL_GPL(pm_runtime_get_if_active); * @dev: Target device. * * Increment the runtime PM usage counter of @dev if its runtime PM status is - * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case - * it returns 1. If the device is in a different state or its usage_count is 0, - * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device, - * in which case also the usage_count will remain unmodified. + * %RPM_ACTIVE and its runtime PM usage counter is greater than 0 or it is not + * ignoring children and its active child count is nonzero. 1 is returned in + * this case. + * + * If @dev is in a different state or it is not in use (that is, its usage + * counter is 0, or it is ignoring children, or its active child count is 0), + * 0 is returned. + * + * -EINVAL is returned if runtime PM is disabled for the device, in which case + * also the usage counter of @dev is not updated. */ int pm_runtime_get_if_in_use(struct device *dev) {