I recently discovered that the acpi-als driver doesn't properly
activate the ambient light sensor in this laptop. The sensor begins in
the off state, and gives a constant brightness value of 0x190 when
queried. The solution is to call the \_SB.PCI0.LPCB.EC0.ALSC method
with an integer argument of 1 when the module is loaded. I have a
patch for this, but I don't know if what it does constitutes proper
testing for the presence of that method, or if I should disable the
sensor when the module is unloaded, so input is welcome on those
details.
--- acpi-als.c.orig 2017-11-09 13:29:43.346699941 -0700
+++ acpi-als.c 2017-11-09 13:35:21.708579014 -0700
@@ -180,6 +180,11 @@
struct acpi_als *als;
struct iio_dev *indio_dev;
struct iio_buffer *buffer;
+ unsigned long long temp_val;
+ acpi_status status;
+ struct acpi_object_list arg_list;
+ union acpi_object arg;
+
indio_dev = devm_iio_device_alloc(&device->dev, sizeof(*als));
if (!indio_dev)
@@ -204,6 +209,18 @@
iio_device_attach_buffer(indio_dev, buffer);
+ arg_list.count = 1;
+ arg_list.pointer = &arg;
+ arg.type = ACPI_TYPE_INTEGER;
+ arg.integer.value = 1;
+
+ if (acpi_has_method(als->device->handle, "\\_SB.PCI0.LPCB.EC0.ALSC")) {
+ status = acpi_evaluate_integer(als->device->handle,
+ "\\_SB.PCI0.LPCB.EC0.ALSC",
+ &arg_list,
+ &temp_val);
+ }
+
return devm_iio_device_register(&device->dev, indio_dev);
}
--
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