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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PCI <linux-pci@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Bjorn Helgaas <helgaas@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Anders Roxell <anders.roxell@linaro.org>
Subject: [PATCH v1 10/11] PCI/PM: Rearrange pci_set_power_state()
Date: Thu, 05 May 2022 20:16:50 +0200	[thread overview]
Message-ID: <2139440.Mh6RI2rZIc@kreacher> (raw)
In-Reply-To: <4738492.GXAFRqVoOG@kreacher>

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

The part of pci_set_power_state() related to transitions into
low-power states is unnecessary convoluted, so clearly divide it
into the D3cold special case and the general case covering all of
the other states.

Also fix a potential issue with calling pci_bus_set_current_state()
to set the current state of all devices on the subordinate bus to
D3cold without checking if the power state of the parent bridge has
really changed to D3cold.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pci/pci.c |   28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -1446,19 +1446,25 @@ int pci_set_power_state(struct pci_dev *
 	if (state >= PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
 		return 0;
 
-	/*
-	 * To put device in D3cold, we put device into D3hot in native
-	 * way, then put device into D3cold with platform ops
-	 */
-	error = pci_set_low_power_state(dev, state > PCI_D3hot ?
-					PCI_D3hot : state);
+	if (state == PCI_D3cold) {
+		/*
+		 * To put the device in D3cold, put it into D3hot in the native
+		 * way, then put it into D3cold using platform ops.
+		 */
+		error = pci_set_low_power_state(dev, PCI_D3hot);
 
-	if (pci_platform_power_transition(dev, state))
-		return error;
+		if (pci_platform_power_transition(dev, PCI_D3cold))
+			return error;
 
-	/* Powering off a bridge may power off the whole hierarchy */
-	if (state == PCI_D3cold)
-		pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
+		/* Powering off a bridge may power off the whole hierarchy */
+		if (dev->current_state == PCI_D3cold)
+			pci_bus_set_current_state(dev->subordinate, PCI_D3cold);
+	} else {
+		error = pci_set_low_power_state(dev, state);
+
+		if (pci_platform_power_transition(dev, state))
+			return error;
+	}
 
 	return 0;
 }




  parent reply	other threads:[~2022-05-05 18:31 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-05 17:57 [PATCH v1 00/11] PCI/PM: Rework powering up PCI devices Rafael J. Wysocki
2022-05-05 18:00 ` [PATCH v1 01/11] PCI/PM: Split pci_raw_set_power_state() Rafael J. Wysocki
2022-05-05 18:02 ` [PATCH v1 02/11] PCI/PM: Relocate pci_set_low_power_state() Rafael J. Wysocki
2022-05-05 18:04 ` [PATCH v1 03/11] PCI/PM: Set current_state to D3cold if the device is not accessible Rafael J. Wysocki
2022-05-05 18:05 ` [PATCH v1 04/11] PCI/PM: Unfold pci_platform_power_transition() in pci_power_up() Rafael J. Wysocki
2022-05-05 18:09 ` [PATCH v1 05/11] PCI/PM: Do not call pci_update_current_state() from pci_power_up() Rafael J. Wysocki
2022-05-05 18:10 ` [PATCH v1 06/11] PCI/PM: Write 0 to PMCSR in pci_power_up() in all cases Rafael J. Wysocki
2022-05-26 16:54   ` Bjorn Helgaas
2022-05-26 19:46     ` Bjorn Helgaas
2022-05-27 18:52       ` Rafael J. Wysocki
2022-05-27 22:51         ` Bjorn Helgaas
2022-05-27 23:09           ` Bjorn Helgaas
2022-05-28 13:59             ` Rafael J. Wysocki
2022-05-05 18:13 ` [PATCH v1 07/11] PCI/PM: Split pci_power_up() Rafael J. Wysocki
2022-05-05 18:14 ` [PATCH v1 08/11] PCI/PM: Do not restore BARs if device is not in D0 Rafael J. Wysocki
2022-05-05 18:15 ` [PATCH v1 09/11] PCI/PM: Clean up pci_set_low_power_state() Rafael J. Wysocki
2022-05-05 18:16 ` Rafael J. Wysocki [this message]
2022-05-05 18:18 ` [PATCH v1 11/11] PCI/PM: Replace pci_set_power_state() in pci_pm_thaw_noirq() Rafael J. Wysocki
2022-05-05 19:22 ` [PATCH v1 00/11] PCI/PM: Rework powering up PCI devices Bjorn Helgaas
2022-05-05 19:44   ` Nathan Chancellor

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