Re: [PATCH v3 4/4] thinkpad-acpi: fix handle locate for video andquery of _BCL

From: Henrique de Moraes Holschuh
Date: Fri Sep 27 2013 - 11:20:46 EST

On Tue, 24 Sep 2013, Aaron Lu wrote:
> 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 <>
> Tested-by: Igor Gnatenko <i.gnatenko.brain@xxxxxxxxx>

Some testing on a *60 (T60,X60...) would also be best, I cannot test this on
my T43.

Anyway, the code itself looks fine, so:

Acked-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>

"One disk to rule them all, One disk to find them. One disk to bring
them all and in the darkness grind them. In the Land of Redmond
where the shadows lie." -- The Silicon Valley Tarot
Henrique Holschuh
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