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Commit 46445b6b authored by Aaron Lu's avatar Aaron Lu Committed by Rafael J. Wysocki
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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: default avatarAaron Lu <aaron.lu@intel.com>
Tested-by: default avatarIgor Gnatenko <i.gnatenko.brain@gmail.com>
Acked-by: default avatarHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent fbc9fe1b

drivers/platform/x86/thinkpad_acpi.c

+24 −7
Original line number Diff line number Diff line
@@ -700,6 +700,14 @@ static void __init drv_acpi_handle_init(const char *name, 
static acpi_status __init tpacpi_acpi_handle_locate_callback(acpi_handle handle,

			u32 level, void *context, void **return_value)

{

	struct acpi_device *dev;

	if (!strcmp(context, "video")) {

		if (acpi_bus_get_device(handle, &dev))

			return AE_OK;

		if (strcmp(ACPI_VIDEO_HID, acpi_device_hid(dev)))

			return AE_OK;

	}



	*(acpi_handle *)return_value = handle;



	return AE_CTRL_TERMINATE;
@@ -712,10 +720,10 @@ static void __init tpacpi_acpi_handle_locate(const char *name, 
	acpi_status status;

	acpi_handle device_found;



	BUG_ON(!name || !hid || !handle);

	BUG_ON(!name || !handle);

	vdbg_printk(TPACPI_DBG_INIT,

			"trying to locate ACPI handle for %s, using HID %s\n",

			name, hid);

			name, hid ? hid : "NULL");



	memset(&device_found, 0, sizeof(device_found));

	status = acpi_get_devices(hid, tpacpi_acpi_handle_locate_callback,
@@ -6090,9 +6098,19 @@ static int __init tpacpi_query_bcl_levels(acpi_handle handle) 
{

	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	union acpi_object *obj;

	struct acpi_device *device, *child;

	int rc;



	if (ACPI_SUCCESS(acpi_evaluate_object(handle, "_BCL", NULL, &buffer))) {

	if (acpi_bus_get_device(handle, &device))

		return 0;



	rc = 0;

	list_for_each_entry(child, &device->children, node) {

		acpi_status status = acpi_evaluate_object(child->handle, "_BCL",

							  NULL, &buffer);

		if (ACPI_FAILURE(status))

			continue;



		obj = (union acpi_object *)buffer.pointer;

		if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {

			pr_err("Unknown _BCL data, please report this to %s\n",
@@ -6101,8 +6119,7 @@ static int __init tpacpi_query_bcl_levels(acpi_handle handle) 
		} else {

			rc = obj->package.count;

		}

	} else {

		return 0;

		break;

	}



	kfree(buffer.pointer);
@@ -6118,7 +6135,7 @@ static unsigned int __init tpacpi_check_std_acpi_brightness_support(void) 
	acpi_handle video_device;

	int bcl_levels = 0;



	tpacpi_acpi_handle_locate("video", ACPI_VIDEO_HID, &video_device);

	tpacpi_acpi_handle_locate("video", NULL, &video_device);

	if (video_device)

		bcl_levels = tpacpi_query_bcl_levels(video_device);