[PATCH 2/2] PM: sleep: Do not arm wakeup IRQs for hibernation freeze and quiesce

[Abel Vesa]

Freezing devices to take a hibernation image and quiescing them before
jumping into one go through the regular noirq suspend path, which arms
the wakeup IRQs of all devices that may wake up the system. A wakeup
IRQ firing then aborts the hibernation or the restore:

  PM: Triggering wakeup from IRQ 180
  Wakeup pending. Abort CPU freeze
  PM: hibernation: Failed to load image, recovering.

On a Qualcomm Glymur CRD this happens on every hibernation and every
restore. The WWAN modem keeps asserting WAKE# once its root port goes
down, after its driver has shut it down for the freeze, and the WAKE#
GPIO of a PCIe port is a dedicated wakeup IRQ with wakeup enabled by
default.

Neither transition is one the system can be woken up from, as nothing
goes to sleep, and Documentation/driver-api/pm/devices.rst already says
that in the freeze_late and freeze_noirq phases a device "should not be
allowed to generate wakeup events". Do not arm the wakeup IRQs for
them, and only disarm them in the noirq resume path if they have been
armed. Wakeup IRQs are still armed for the final transition to sleep,
PM_EVENT_HIBERNATE, and for suspend.

Signed-off-by: Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx>
---
 drivers/base/power/main.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 16a1f017051e..34ba0e5941a3 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -949,6 +949,9 @@ static void dpm_noirq_resume_devices(pm_message_t state)
 	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
 }
 
+/* Whether dpm_suspend_noirq() has armed the wakeup IRQs of devices */
+static bool dpm_wake_irqs_armed;
+
 /**
  * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
  * @state: PM transition of the system being carried out.
@@ -961,7 +964,11 @@ void dpm_resume_noirq(pm_message_t state)
 	dpm_noirq_resume_devices(state);
 
 	resume_device_irqs();
-	device_wakeup_disarm_wake_irqs();
+
+	if (dpm_wake_irqs_armed) {
+		device_wakeup_disarm_wake_irqs();
+		dpm_wake_irqs_armed = false;
+	}
 }
 
 static void async_resume_early(void *data, async_cookie_t cookie);
@@ -1685,7 +1692,17 @@ int dpm_suspend_noirq(pm_message_t state)
 {
 	int ret;
 
-	device_wakeup_arm_wake_irqs();
+	/*
+	 * Freezing devices to take a hibernation image, and quiescing them
+	 * before jumping into one, are not transitions the system can be woken
+	 * up from, as nothing goes to sleep. A wakeup IRQ of a device that
+	 * signals for attention once its link goes down, like a PCIe endpoint
+	 * asserting WAKE#, would only abort the hibernation or the restore.
+	 */
+	if (state.event != PM_EVENT_FREEZE && state.event != PM_EVENT_QUIESCE) {
+		device_wakeup_arm_wake_irqs();
+		dpm_wake_irqs_armed = true;
+	}
 	suspend_device_irqs();
 
 	ret = dpm_noirq_suspend_devices(state);

-- 
2.54.0