Some BIOSes unconditionally send an ACPI notification to RBTN when the
system is resuming from suspend. This makes dell-rbtn send an input
event to userspace as if a function key was pressed. Prevent this by
ignoring all the notifications received while the device is suspended.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=106031
Signed-off-by: Gabriele Mazzotta <gabriele....@gmail.com>
---
 drivers/platform/x86/dell-rbtn.c | 41 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c
index cd410e3..56b0da7 100644
--- a/drivers/platform/x86/dell-rbtn.c
+++ b/drivers/platform/x86/dell-rbtn.c
@@ -28,6 +28,7 @@ struct rbtn_data {
        enum rbtn_type type;
        struct rfkill *rfkill;
        struct input_dev *input_dev;
+       bool suspended;
 };
 
 
@@ -220,9 +221,44 @@ static const struct acpi_device_id rbtn_ids[] = {
        { "", 0 },
 };
 
+#ifdef CONFIG_PM_SLEEP
+static void ACPI_SYSTEM_XFACE rbtn_acpi_clear_flag(void *context)
+{
+       struct rbtn_data *rbtn_data = context;
+
+       rbtn_data->suspended = false;
+}
+
+static int rbtn_suspend(struct device *dev)
+{
+       struct acpi_device *device = to_acpi_device(dev);
+       struct rbtn_data *rbtn_data = acpi_driver_data(device);
+
+       rbtn_data->suspended = true;
+
+       return 0;
+}
+
+static int rbtn_resume(struct device *dev)
+{
+       struct acpi_device *device = to_acpi_device(dev);
+       struct rbtn_data *rbtn_data = acpi_driver_data(device);
+       acpi_status status;
+
+       status = acpi_os_execute(OSL_NOTIFY_HANDLER,
+                        rbtn_acpi_clear_flag, rbtn_data);
+       if (ACPI_FAILURE(status))
+               rbtn_data->suspended = false;
+
+       return 0;
+}
+#endif
+static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
+
 static struct acpi_driver rbtn_driver = {
        .name = "dell-rbtn",
        .ids = rbtn_ids,
+       .drv.pm = &rbtn_pm_ops,
        .ops = {
                .add = rbtn_add,
                .remove = rbtn_remove,
@@ -384,6 +420,11 @@ static void rbtn_notify(struct acpi_device *device, u32 
event)
 {
        struct rbtn_data *rbtn_data = device->driver_data;
 
+       if (rbtn_data->suspended) {
+               dev_dbg(&device->dev, "ACPI notification ignored\n");
+               return;
+       }
+
        if (event != 0x80) {
                dev_info(&device->dev, "Received unknown event (0x%x)\n",
                         event);
-- 
2.7.0

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