linux-kernel - [PATCH v7 1/2] PCI/PM: refactor pci_pm_suspend

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Message-Id: <20220609001007.533242-1-rajvi.jingar@linux.intel.com>
Date:   Wed,  8 Jun 2022 17:10:06 -0700
From:   Rajvi Jingar <rajvi.jingar@...ux.intel.com>
To:     rafael.j.wysocki@...el.com, bhelgaas@...gle.com
Cc:     rajvi.jingar@...ux.intel.com, david.e.box@...ux.intel.com,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: [PATCH v7 1/2] PCI/PM: refactor pci_pm_suspend_noirq()

The state of the device is saved during pci_pm_suspend_noirq(), if it
has not already been saved, regardless of the skip_bus_pm flag value. So
skip_bus_pm check is removed before saving the device state.

Signed-off-by: Rajvi Jingar <rajvi.jingar@...ux.intel.com>
Suggested-by: David E. Box <david.e.box@...ux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 v1 -> v2: add comments to the changes
 v2 -> v3: move changelog after "---" marker
 v3 -> v4: add "---" marker after changelog
 v4 -> v5: no change
 v5 -> v6: no change
 v6 -> v7: no change
---
 drivers/pci/pci-driver.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 49238ddd39ee..1f64de3e5280 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -867,20 +867,14 @@ static int pci_pm_suspend_noirq(struct device *dev)
 		}
 	}
 
-	if (pci_dev->skip_bus_pm) {
+	if (!pci_dev->state_saved) {
+		pci_save_state(pci_dev);
 		/*
-		 * Either the device is a bridge with a child in D0 below it, or
-		 * the function is running for the second time in a row without
-		 * going through full resume, which is possible only during
-		 * suspend-to-idle in a spurious wakeup case.  The device should
-		 * be in D0 at this point, but if it is a bridge, it may be
-		 * necessary to save its state.
+		 * If the device is a bridge with a child in D0 below it, it needs to
+		 * stay in D0, so check skip_bus_pm to avoid putting it into a
+		 * low-power state in that case.
 		 */
-		if (!pci_dev->state_saved)
-			pci_save_state(pci_dev);
-	} else if (!pci_dev->state_saved) {
-		pci_save_state(pci_dev);
-		if (pci_power_manageable(pci_dev))
+		if (!pci_dev->skip_bus_pm && pci_power_manageable(pci_dev))
 			pci_prepare_to_sleep(pci_dev);
 	}
 
-- 
2.25.1