Patch "gpiolib: acpi: Do not set the IRQ type if the IRQ is already in use" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    gpiolib: acpi: Do not set the IRQ type if the IRQ is already in use

to the 5.10-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:
     gpiolib-acpi-do-not-set-the-irq-type-if-the-irq-is-a.patch
and it can be found in the queue-5.10 subdirectory.

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



commit b6e7ae40f72a24ab66958e60c64eb3687109b15e
Author: Hans de Goede <hdegoede@xxxxxxxxxx>
Date:   Thu Nov 25 21:30:10 2021 +0100

    gpiolib: acpi: Do not set the IRQ type if the IRQ is already in use
    
    [ Upstream commit bdfd6ab8fdccd8b138837efff66f4a1911496378 ]
    
    If the IRQ is already in use, then acpi_dev_gpio_irq_get_by() really
    should not change the type underneath the current owner.
    
    I specifically hit an issue with this an a Chuwi Hi8 Super (CWI509) Bay
    Trail tablet, when the Boot OS selection in the BIOS is set to Android.
    In this case _STA for a MAX17047 ACPI I2C device wrongly returns 0xf and
    the _CRS resources for this device include a GpioInt pointing to a GPIO
    already in use by an _AEI handler, with a different type then specified
    in the _CRS for the MAX17047 device. Leading to the acpi_dev_gpio_irq_get()
    call done by the i2c-core-acpi.c code changing the type breaking the
    _AEI handler.
    
    Now this clearly is a bug in the DSDT of this tablet (in Android mode),
    but in general calling irq_set_irq_type() on an IRQ which already is
    in use seems like a bad idea.
    
    Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
    Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 6f11714ce0239..55e4f402ec8b6 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -969,10 +969,17 @@ int acpi_dev_gpio_irq_get_by(struct acpi_device *adev, const char *name, int ind
 			irq_flags = acpi_dev_get_irq_type(info.triggering,
 							  info.polarity);
 
-			/* Set type if specified and different than the current one */
-			if (irq_flags != IRQ_TYPE_NONE &&
-			    irq_flags != irq_get_trigger_type(irq))
-				irq_set_irq_type(irq, irq_flags);
+			/*
+			 * If the IRQ is not already in use then set type
+			 * if specified and different than the current one.
+			 */
+			if (can_request_irq(irq, irq_flags)) {
+				if (irq_flags != IRQ_TYPE_NONE &&
+				    irq_flags != irq_get_trigger_type(irq))
+					irq_set_irq_type(irq, irq_flags);
+			} else {
+				dev_dbg(&adev->dev, "IRQ %d already in use\n", irq);
+			}
 
 			return irq;
 		}