linux-kernel - [PATCH 4.9 63/94] PCI/PM: Add needs_resume flag to avoid suspend complete optimization

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Message-Id: <20170605153105.848067565@linuxfoundation.org>
Date:   Mon,  5 Jun 2017 18:17:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Imre Deak <imre.deak@...el.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 4.9 63/94] PCI/PM: Add needs_resume flag to avoid suspend complete optimization

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Imre Deak <imre.deak@...el.com>

commit 4d071c3238987325b9e50e33051a40d1cce311cc upstream.

Some drivers - like i915 - may not support the system suspend direct
complete optimization due to differences in their runtime and system
suspend sequence.  Add a flag that when set resumes the device before
calling the driver's system suspend handlers which effectively disables
the optimization.

Needed by a future patch fixing suspend/resume on i915.

Suggested by Rafael.

Signed-off-by: Imre Deak <imre.deak@...el.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/pci/pci.c   |    3 ++-
 include/linux/pci.h |    5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2142,7 +2142,8 @@ bool pci_dev_keep_suspended(struct pci_d
 
 	if (!pm_runtime_suspended(dev)
 	    || pci_target_state(pci_dev) != pci_dev->current_state
-	    || platform_pci_need_resume(pci_dev))
+	    || platform_pci_need_resume(pci_dev)
+	    || (pci_dev->dev_flags & PCI_DEV_FLAGS_NEEDS_RESUME))
 		return false;
 
 	/*
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -178,6 +178,11 @@ enum pci_dev_flags {
 	PCI_DEV_FLAGS_NO_PM_RESET = (__force pci_dev_flags_t) (1 << 7),
 	/* Get VPD from function 0 VPD */
 	PCI_DEV_FLAGS_VPD_REF_F0 = (__force pci_dev_flags_t) (1 << 8),
+	/*
+	 * Resume before calling the driver's system suspend hooks, disabling
+	 * the direct_complete optimization.
+	 */
+	PCI_DEV_FLAGS_NEEDS_RESUME = (__force pci_dev_flags_t) (1 << 11),
 };
 
 enum pci_irq_reroute_variant {