[PATCH v2 9/9] PCI/PM: Replace pci_set_power_state() in pci_pm_thaw_noirq()

From: Rafael J. Wysocki
Date: Mon Apr 11 2022 - 10:34:12 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

Calling pci_set_power_state() to put the given device into D0 in
pci_pm_thaw_noirq() may cause it to restore the device's BARs, which
is redundant before calling pci_restore_state(), so replace it with
a direct pci_power_up() call followed by pci_update_current_state()
if it returns a nonzeor value, in analogy with
pci_pm_default_resume_early().

Avoid code duplication by introducing a wrapper function to contain
the repeating pattern and calling it in both places.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---

New patch in v2.

---
drivers/pci/pci-driver.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -551,11 +551,15 @@ static void pci_pm_default_resume(struct
pci_enable_wake(pci_dev, PCI_D0, false);
}

-static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
+static void pci_pm_power_up_and_verify_state(struct pci_dev *pci_dev)
{
if (pci_power_up(pci_dev))
pci_update_current_state(pci_dev, PCI_D0);
+}

+static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
+{
+ pci_pm_power_up_and_verify_state(pci_dev);
pci_restore_state(pci_dev);
pci_pme_restore(pci_dev);
}
@@ -1080,7 +1084,7 @@ static int pci_pm_thaw_noirq(struct devi
* in case the driver's "freeze" callbacks put it into a low-power
* state.
*/
- pci_set_power_state(pci_dev, PCI_D0);
+ pci_pm_power_up_and_verify_state(pci_dev);
pci_restore_state(pci_dev);

if (pci_has_legacy_pm_support(pci_dev))