[PATCH 5.4 168/320] gpiolib: acpi: Do not set the IRQ type if the IRQ is already in use

Greg Kroah-Hartman
2022-01-24T19:40:49Z

From: Hans de Goede <hdegoede@redhat.com>

[ 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@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpio/gpiolib-acpi.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index e3ddc99c105d4..13c6eee481da7 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -953,10 +953,17 @@ int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
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;
}
--
2.34.1