[PATCH 1/2] Input: soc_button_array - Add use_low_level_irq module parameter

[Hans de Goede <hdegoede@redhat.com>]

It seems that the Windows drivers for the ACPI0011 soc_button_array
device use low level triggered IRQs rather then using edge triggering.

Some ACPI tables depend on this, directly poking the GPIO controller's
registers to clear the trigger type when closing a laptop's/2-in-1's lid
and re-instating the trigger when opening the lid again.

Linux sets the edge/level on which to trigger to both low+high since
it is using edge type IRQs, the ACPI tables then ends up also setting
the bit for level IRQs and since both low and high level have been
selected by Linux we get an IRQ storm leading to soft lockups.

As a workaround for this the soc_button_array already contains
a DMI quirk table with device models known to have this issue.

Add a module parameter for this so that users can easily test if their
device is affected too and so that they can use the module parameter
as a workaround.

Cc: Rudolf Polzer <rpolzer@google.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/input/misc/soc_button_array.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/input/misc/soc_button_array.c b/drivers/input/misc/soc_button_array.c
index 480476121c01..50497dd05027 100644
--- a/drivers/input/misc/soc_button_array.c
+++ b/drivers/input/misc/soc_button_array.c
@@ -18,6 +18,10 @@
 #include <linux/gpio.h>
 #include <linux/platform_device.h>
 
+static bool use_low_level_irq;
+module_param(use_low_level_irq, bool, 0444);
+MODULE_PARM_DESC(use_low_level_irq, "Use low-level triggered IRQ instead of edge triggered");
+
 struct soc_button_info {
 	const char *name;
 	int acpi_index;
@@ -164,7 +168,8 @@ soc_button_device_create(struct platform_device *pdev,
 		}
 
 		/* See dmi_use_low_level_irq[] comment */
-		if (!autorepeat && dmi_check_system(dmi_use_low_level_irq)) {
+		if (!autorepeat && (use_low_level_irq ||
+				    dmi_check_system(dmi_use_low_level_irq))) {
 			irq_set_irq_type(irq, IRQ_TYPE_LEVEL_LOW);
 			gpio_keys[n_buttons].irq = irq;
 			gpio_keys[n_buttons].gpio = -ENOENT;
-- 
2.37.3