diff options
| author | Henrique de Moraes Holschuh <hmh@hmh.eng.br> | 2010-08-09 23:48:18 -0300 |
|---|---|---|
| committer | Matthew Garrett <mjg@redhat.com> | 2010-08-16 11:54:47 -0400 |
| commit | 122f26726b5e16174bf8a707df14be1d93c49d62 (patch) | |
| tree | 7e71e1fa0c2dda912796f1cb9fd1f1f71bb872e4 /drivers/platform/x86/thinkpad_acpi.c | |
| parent | 52d7ee558d3babb4918eed6769f593adc1b6616e (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>
Diffstat (limited to 'drivers/platform/x86/thinkpad_acpi.c')
| -rw-r--r-- | drivers/platform/x86/thinkpad_acpi.c | 52 |
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; } /* |