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authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>2010-08-09 23:48:18 -0300
committerMatthew Garrett <mjg@redhat.com>2010-08-16 11:54:47 -0400
commit122f26726b5e16174bf8a707df14be1d93c49d62 (patch)
tree7e71e1fa0c2dda912796f1cb9fd1f1f71bb872e4
parent52d7ee558d3babb4918eed6769f593adc1b6616e (diff)
thinkpad-acpi: find ACPI video device by synthetic HID
The Linux ACPI core locates the ACPI video devices for us and marks them with ACPI_VIDEO_HID. Use that information to locate the video device instead of a half-baked hunt for _BCL. This uncouples the detection of the number of backlight brightness levels on ThinkPads from the ACPI paths in vid_handle. With this change, the driver should be able to always detect whether the ThinkPad uses a 8-level or 16-level brightness scale even on newer models for which the vid_handle paths have not been updated yet. It will skip deactivated devices in the ACPI device tree, which is a change in behaviour. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Signed-off-by: Matthew Garrett <mjg@redhat.com>
-rw-r--r--drivers/platform/x86/thinkpad_acpi.c52
1 files changed, 12 insertions, 40 deletions
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 5d6119bed00c..9d6fc4c7c08e 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -6080,13 +6080,18 @@ static struct backlight_ops ibm_backlight_data = {
/* --------------------------------------------------------------------- */
+/*
+ * Call _BCL method of video device. On some ThinkPads this will
+ * switch the firmware to the ACPI brightness control mode.
+ */
+
static int __init tpacpi_query_bcl_levels(acpi_handle handle)
{
struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
union acpi_object *obj;
int rc;
- if (ACPI_SUCCESS(acpi_evaluate_object(handle, NULL, NULL, &buffer))) {
+ if (ACPI_SUCCESS(acpi_evaluate_object(handle, "_BCL", NULL, &buffer))) {
obj = (union acpi_object *)buffer.pointer;
if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
printk(TPACPI_ERR "Unknown _BCL data, "
@@ -6103,55 +6108,22 @@ static int __init tpacpi_query_bcl_levels(acpi_handle handle)
return rc;
}
-static acpi_status __init tpacpi_acpi_walk_find_bcl(acpi_handle handle,
- u32 lvl, void *context, void **rv)
-{
- char name[ACPI_PATH_SEGMENT_LENGTH];
- struct acpi_buffer buffer = { sizeof(name), &name };
-
- if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer)) &&
- !strncmp("_BCL", name, sizeof(name) - 1)) {
- BUG_ON(!rv || !*rv);
- **(int **)rv = tpacpi_query_bcl_levels(handle);
- return AE_CTRL_TERMINATE;
- } else {
- return AE_OK;
- }
-}
/*
* Returns 0 (no ACPI _BCL or _BCL invalid), or size of brightness map
*/
static unsigned int __init tpacpi_check_std_acpi_brightness_support(void)
{
- int status;
+ acpi_handle video_device;
int bcl_levels = 0;
- void *bcl_ptr = &bcl_levels;
- if (!vid_handle)
- TPACPI_ACPIHANDLE_INIT(vid);
+ tpacpi_acpi_handle_locate("video", ACPI_VIDEO_HID, &video_device);
+ if (video_device)
+ bcl_levels = tpacpi_query_bcl_levels(video_device);
- if (!vid_handle)
- return 0;
-
- /*
- * Search for a _BCL method, and execute it. This is safe on all
- * ThinkPads, and as a side-effect, _BCL will place a Lenovo Vista
- * BIOS in ACPI backlight control mode. We do NOT have to care
- * about calling the _BCL method in an enabled video device, any
- * will do for our purposes.
- */
+ tp_features.bright_acpimode = (bcl_levels > 0);
- status = acpi_walk_namespace(ACPI_TYPE_METHOD, vid_handle, 3,
- tpacpi_acpi_walk_find_bcl, NULL, NULL,
- &bcl_ptr);
-
- if (ACPI_SUCCESS(status) && bcl_levels > 2) {
- tp_features.bright_acpimode = 1;
- return bcl_levels - 2;
- }
-
- return 0;
+ return (bcl_levels > 2) ? (bcl_levels - 2) : 0;
}
/*

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