linux-kernel - [PATCH v1 3/5] PCI: PM: Rearrange code in pci_target

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Date:   Sat, 18 Sep 2021 15:24:46 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux ACPI <linux-acpi@...r.kernel.org>,
        Linux PCI <linux-pci@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        x86 Maintainers <x86@...nel.org>
Subject: [PATCH v1 3/5] PCI: PM: Rearrange code in  pci_target_state()

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

Make pci_target_state() return D3cold or D0 without checking PME
support if the current power state of the device is D3cold or if it
does not support the standard PCI PM, respectively.

Next, drop the tergat_state local variable that has become redundant
from that function.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/pci/pci.c |   23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -2520,8 +2520,6 @@ EXPORT_SYMBOL(pci_wake_from_d3);
  */
 static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 {
-	pci_power_t target_state = PCI_D3hot;
-
 	if (acpi_pci_power_manageable(dev)) {
 		/*
 		 * Use ACPI to find the target state for the device.  If it
@@ -2533,32 +2531,29 @@ static pci_power_t pci_target_state(stru
 		switch (state) {
 		case PCI_POWER_ERROR:
 		case PCI_UNKNOWN:
-			break;
+			return PCI_D3hot;
+
 		case PCI_D1:
 		case PCI_D2:
 			if (pci_no_d1d2(dev))
-				break;
-			fallthrough;
-		default:
-			target_state = state;
+				return PCI_D3hot;
 		}
 
-		return target_state;
+		return state;
 	}
 
-	if (!dev->pm_cap)
-		target_state = PCI_D0;
-
 	/*
 	 * If the device is in D3cold even though it's not power-manageable by
 	 * the platform, it may have been powered down by non-standard means.
 	 * Best to let it slumber.
 	 */
 	if (dev->current_state == PCI_D3cold)
-		target_state = PCI_D3cold;
+		return PCI_D3cold;
+	else if (!dev->pm_cap)
+		return PCI_D0;
 
 	if (wakeup && dev->pme_support) {
-		pci_power_t state = target_state;
+		pci_power_t state = PCI_D3hot;
 
 		/*
 		 * Find the deepest state from which the device can generate
@@ -2573,7 +2568,7 @@ static pci_power_t pci_target_state(stru
 			return PCI_D0;
 	}
 
-	return target_state;
+	return PCI_D3hot;
 }
 
 /**