linux-kernel - [char-misc 1/2] mei: always use domain runtime pm callbacks.

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Date:   Sun, 24 Sep 2017 11:35:33 +0300
From:   Tomas Winkler <tomas.winkler@...el.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-kernel@...r.kernel.org, "#4 . 13+" <stable@...r.kernel.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc 1/2] mei: always use domain runtime pm callbacks.

From: Alexander Usyskin <alexander.usyskin@...el.com>

This patch fixes a regression caused by the new changes
in the run wake handlers, pci_dev_run_wake() return true
when wake is possible from the software perspective
not whether it is actually enabled.

The mei devices that support D0i3 are no longer receiving an interrupt
after entering runtime suspend state and will stall.

MEI maps runtime suspend/resume to its own defined
power gating (PG) states, (D0i3 or other depending on generation),
hence we need to go around the native PCI runtime service which
eventually brings the device into D3cold/hot state,
but the mei devices cannot wake up from D3 unlike from D0i3/PG state,
which keeps irq running.
To get around PCI device native runtime pm,
MEI uses runtime pm domain handlers which take precedence.

Cc: <stable@...r.kernel.org> #4.13+
Cc: Rafael J. Wysocki <rafael@...nel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/pci-me.c  | 21 +++++++++++----------
 drivers/misc/mei/pci-txe.c | 30 +++++++++++-------------------
 2 files changed, 22 insertions(+), 29 deletions(-)

diff --git a/drivers/misc/mei/pci-me.c b/drivers/misc/mei/pci-me.c
index 4ff40d319676..630757a4b36a 100644
--- a/drivers/misc/mei/pci-me.c
+++ b/drivers/misc/mei/pci-me.c
@@ -226,12 +226,15 @@ static int mei_me_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	pdev->dev_flags |= PCI_DEV_FLAGS_NEEDS_RESUME;
 
 	/*
-	* For not wake-able HW runtime pm framework
-	* can't be used on pci device level.
-	* Use domain runtime pm callbacks instead.
-	*/
-	if (!pci_dev_run_wake(pdev))
-		mei_me_set_pm_domain(dev);
+	 * ME maps runtime suspend/resume to D0i states,
+	 * hence we need to go around native PCI runtime service which
+	 * eventually brings the device into D3cold/hot state,
+	 * but the mei device cannot wake up from D3 unlike from D0i3.
+	 * To get around the PCI device native runtime pm,
+	 * ME uses runtime pm domain handlers which take precedence
+	 * over the driver's pm handlers.
+	 */
+	mei_me_set_pm_domain(dev);
 
 	if (mei_pg_is_enabled(dev))
 		pm_runtime_put_noidle(&pdev->dev);
@@ -271,8 +274,7 @@ static void mei_me_shutdown(struct pci_dev *pdev)
 	dev_dbg(&pdev->dev, "shutdown\n");
 	mei_stop(dev);
 
-	if (!pci_dev_run_wake(pdev))
-		mei_me_unset_pm_domain(dev);
+	mei_me_unset_pm_domain(dev);
 
 	mei_disable_interrupts(dev);
 	free_irq(pdev->irq, dev);
@@ -300,8 +302,7 @@ static void mei_me_remove(struct pci_dev *pdev)
 	dev_dbg(&pdev->dev, "stop\n");
 	mei_stop(dev);
 
-	if (!pci_dev_run_wake(pdev))
-		mei_me_unset_pm_domain(dev);
+	mei_me_unset_pm_domain(dev);
 
 	mei_disable_interrupts(dev);
 
diff --git a/drivers/misc/mei/pci-txe.c b/drivers/misc/mei/pci-txe.c
index e38a5f144373..0566f9bfa7de 100644
--- a/drivers/misc/mei/pci-txe.c
+++ b/drivers/misc/mei/pci-txe.c
@@ -144,12 +144,14 @@ static int mei_txe_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	pdev->dev_flags |= PCI_DEV_FLAGS_NEEDS_RESUME;
 
 	/*
-	* For not wake-able HW runtime pm framework
-	* can't be used on pci device level.
-	* Use domain runtime pm callbacks instead.
-	*/
-	if (!pci_dev_run_wake(pdev))
-		mei_txe_set_pm_domain(dev);
+	 * TXE maps runtime suspend/resume to own power gating states,
+	 * hence we need to go around native PCI runtime service which
+	 * eventually brings the device into D3cold/hot state.
+	 * But the TXE device cannot wake up from D3 unlike from own
+	 * power gating. To get around PCI device native runtime pm,
+	 * TXE uses runtime pm domain handlers which take precedence.
+	 */
+	mei_txe_set_pm_domain(dev);
 
 	pm_runtime_put_noidle(&pdev->dev);
 
@@ -186,8 +188,7 @@ static void mei_txe_shutdown(struct pci_dev *pdev)
 	dev_dbg(&pdev->dev, "shutdown\n");
 	mei_stop(dev);
 
-	if (!pci_dev_run_wake(pdev))
-		mei_txe_unset_pm_domain(dev);
+	mei_txe_unset_pm_domain(dev);
 
 	mei_disable_interrupts(dev);
 	free_irq(pdev->irq, dev);
@@ -215,8 +216,7 @@ static void mei_txe_remove(struct pci_dev *pdev)
 
 	mei_stop(dev);
 
-	if (!pci_dev_run_wake(pdev))
-		mei_txe_unset_pm_domain(dev);
+	mei_txe_unset_pm_domain(dev);
 
 	mei_disable_interrupts(dev);
 	free_irq(pdev->irq, dev);
@@ -318,15 +318,7 @@ static int mei_txe_pm_runtime_suspend(struct device *device)
 	else
 		ret = -EAGAIN;
 
-	/*
-	 * If everything is okay we're about to enter PCI low
-	 * power state (D3) therefor we need to disable the
-	 * interrupts towards host.
-	 * However if device is not wakeable we do not enter
-	 * D-low state and we need to keep the interrupt kicking
-	 */
-	if (!ret && pci_dev_run_wake(pdev))
-		mei_disable_interrupts(dev);
+	/* keep irq on we are staying in D0 */
 
 	dev_dbg(&pdev->dev, "rpm: txe: runtime suspend ret=%d\n", ret);
 
-- 
2.9.5