[char-misc 01/02 v2] mei: always use domain runtime pm callbacks.

[char-misc 01/02 v2] mei: always use domain runtime pm callbacks.

[Tomas Winkler]

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

This patch fixes a regression caused by the new changes
in the "run wake" handlers.

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

pci_dev_run_wake function now returns "true" for some devices
(including mei) for which it used to return "false",
arguably incorrectly as "run wake" used to mean that
wakeup signals can be generated for a device in
the working state of the system, so it could not be enabled
or disabled before too.

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@vger.kernel.org> #4.13+
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V2: Fix the commit message according Rafael's comment

 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

Re: [char-misc 01/02 v2] mei: always use domain runtime pm callbacks.

[Rafael J. Wysocki]

On Tue, Sep 26, 2017 at 8:18 AM, Tomas Winkler <tomas.winkler@intel.com> wrote:
> From: Alexander Usyskin <alexander.usyskin@intel.com>
>
> This patch fixes a regression caused by the new changes
> in the "run wake" handlers.
>
> The mei devices that support D0i3 are no longer receiving an interrupt
> after entering runtime suspend state and will stall.
>
> pci_dev_run_wake function now returns "true" for some devices
> (including mei) for which it used to return "false",
> arguably incorrectly as "run wake" used to mean that
> wakeup signals can be generated for a device in
> the working state of the system, so it could not be enabled
> or disabled before too.
>
> 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@vger.kernel.org> #4.13+
> Cc: Rafael J. Wysocki <rafael@kernel.org>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>