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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PCI <linux-pci@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Linux ACPI <linux-acpi@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Bjorn Helgaas <helgaas@kernel.org>,
	Kai-Heng Feng <kai.heng.feng@canonical.com>,
	Utkarsh H Patel <utkarsh.h.patel@intel.com>,
	Koba Ko <koba.ko@canonical.com>
Subject: [PATCH v1 1/2] PCI: PM: Add special case handling for PCIe device wakeup
Date: Thu, 29 Jul 2021 16:48:14 +0200	[thread overview]
Message-ID: <2207145.ElGaqSPkdT@kreacher> (raw)
In-Reply-To: <4668274.31r3eYUQgx@kreacher>

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

It is inconsistent to return PCI_D0 from pci_target_state() instead
of the original target state if 'wakeup' is true and the device
cannot signal PME from D0.

This only happens when the device cannot signal PME from the original
target state and any shallower power states (including D0) and that
case is effectively equivalent to the one in which PME signaling is
not supported at all.  Since the original target state is returned in
the latter case, make the function do that in the former one too.

Link: https://lore.kernel.org/linux-pm/3149540.aeNJFYEL58@kreacher/
Fixes: 666ff6f83e1d ("PCI/PM: Avoid using device_may_wakeup() for runtime PM")
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reported-by: Utkarsh H Patel <utkarsh.h.patel@intel.com>
Reported-by: Koba Ko <koba.ko@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/pci/pci.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -2595,16 +2595,20 @@ static pci_power_t pci_target_state(stru
 	if (dev->current_state == PCI_D3cold)
 		target_state = PCI_D3cold;
 
-	if (wakeup) {
+	if (wakeup && dev->pme_support) {
+		pci_power_t state = target_state;
+
 		/*
 		 * Find the deepest state from which the device can generate
 		 * PME#.
 		 */
-		if (dev->pme_support) {
-			while (target_state
-			      && !(dev->pme_support & (1 << target_state)))
-				target_state--;
-		}
+		while (state && !(dev->pme_support & (1 << state)))
+			state--;
+
+		if (state)
+			return state;
+		else if (dev->pme_support & 1)
+			return PCI_D0;
 	}
 
 	return target_state;




  reply	other threads:[~2021-07-29 14:49 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-29 14:46 [PATCH v1 0/2] PCI: PM: Fix handling of device that can only signal PME from D3cold Rafael J. Wysocki
2021-07-29 14:48 ` Rafael J. Wysocki [this message]
2021-07-29 15:09   ` [PATCH v1 1/2] PCI: PM: Add special case handling for PCIe device wakeup Rafael J. Wysocki
2021-07-29 15:54   ` [PATCH v1.1 1/2] PCI: PM: Avoid forcing PCI_D0 for wakeup reasons inconsistently Rafael J. Wysocki
2021-07-30 10:26     ` Mika Westerberg
2021-07-29 14:49 ` [PATCH v1 2/2] PCI: PM: Enable PME if it can be signaled from D3cold Rafael J. Wysocki
2021-07-30 10:28   ` Mika Westerberg
2021-07-30 12:13     ` Rafael J. Wysocki

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