Patch "pinctrl: cherryview: Prevent possible interrupt storm on resume" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    pinctrl: cherryview: Prevent possible interrupt storm on resume

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pinctrl-cherryview-prevent-possible-interrupt-storm-on-resume.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d2cdf5dc58f6970e9d9d26e47974c21fe87983f3 Mon Sep 17 00:00:00 2001
From: Mika Westerberg <mika.westerberg@linux.intel.com>
Date: Mon, 31 Oct 2016 16:57:33 +0200
Subject: pinctrl: cherryview: Prevent possible interrupt storm on resume

From: Mika Westerberg <mika.westerberg@linux.intel.com>

commit d2cdf5dc58f6970e9d9d26e47974c21fe87983f3 upstream.

When the system is suspended to S3 the BIOS might re-initialize certain
GPIO pins back to their original state or it may re-program interrupt mask
of others. For example Acer TravelMate B116-M had BIOS bug where certain
GPIO pin (MF_ISH_GPIO_5) was programmed to trigger on high level, and the
pin state was high once the BIOS gave control to the OS on resume.

This triggers lots of messages like:

 irq 117, desc: ffff88017a61e600, depth: 1, count: 0, unhandled: 0
 ->handle_irq():  ffffffff8109b613, handle_bad_irq+0x0/0x1e0
 ->irq_data.chip(): ffffffffa0020180, chv_pinctrl_exit+0x2d84/0x12 [pinctrl_cherryview]
 ->action():           (null)
    IRQ_NOPROBE set

We reset the mask back to known state in chv_pinctrl_resume() but that is
called only after device interrupts have already been enabled.

Now, this particular issue was fixed by upgrading the BIOS to the latest
(v1.23) but not everybody upgrades their BIOSes so we fix it up in the
driver as well.

Prevent the possible interrupt storm by moving suspend and resume hooks to
be called at _noirq time instead. Since device interrupts are still
disabled we can restore the mask back to known state before interrupt storm
happens.

Reported-by: Christian Steiner <christian.steiner@outlook.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pinctrl/intel/pinctrl-cherryview.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -1564,7 +1564,7 @@ static int chv_pinctrl_remove(struct pla
 }
 
 #ifdef CONFIG_PM_SLEEP
-static int chv_pinctrl_suspend(struct device *dev)
+static int chv_pinctrl_suspend_noirq(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
@@ -1598,7 +1598,7 @@ static int chv_pinctrl_suspend(struct de
 	return 0;
 }
 
-static int chv_pinctrl_resume(struct device *dev)
+static int chv_pinctrl_resume_noirq(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
@@ -1658,7 +1658,8 @@ static int chv_pinctrl_resume(struct dev
 #endif
 
 static const struct dev_pm_ops chv_pinctrl_pm_ops = {
-	SET_LATE_SYSTEM_SLEEP_PM_OPS(chv_pinctrl_suspend, chv_pinctrl_resume)
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(chv_pinctrl_suspend_noirq,
+				      chv_pinctrl_resume_noirq)
 };
 
 static const struct acpi_device_id chv_pinctrl_acpi_match[] = {


Patches currently in stable-queue which might be from mika.westerberg@linux.intel.com are

queue-4.4/pinctrl-cherryview-prevent-possible-interrupt-storm-on-resume.patch
queue-4.4/pinctrl-cherryview-serialize-register-access-in-suspend-resume.patch