thinkpad-acpi: fix handle locate for video and query of _BCL
thinkpad-acpi: fix handle locate for video and query of _BCL

The tpacpi_acpi_handle_locate function makes use of acpi_get_devices to
locate handle for ACPI video by HID, the problem is, ACPI video node
doesn't really have HID defined(i.e. no _HID control method is defined
for video device), so.. that function would fail. This can be solved by
enhancing the callback function for acpi_get_devices, where we can use
acpi_device_hid function to check if the ACPI node corresponds to a
video controller.

In addition to that, the _BCL control method only exists under a video
output device node, not a video controller device node. So to evaluate
_BCL, we need the handle of a video output device node, which is child
of the located video controller node from tpacpi_acpi_handle_locate.

The two fix are necessary for some Thinkpad models to emit notification
on backlight hotkey press as a result of evaluation of _BCL.

Signed-off-by: Aaron Lu <e835aaae27ef45c770cbc83733586d01aadc3a43@intel.com>
Tested-by: Igor Gnatenko <c869b0bfe2cf1da26c2efd33f6d6d74ddcbbdd2b@gmail.com>
Acked-by: Henrique de Moraes Holschuh <1416ae054606eb9be8fa0d7696a4ddff667a3601@hmh.eng.br>
Signed-off-by: Rafael J. Wysocki <27ffc44a8ec6a212fba98cfc3246c6ce8ab131e0@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs