[PATCH 92/98] ACPI video: support _BQC/_BCL/_BCM methods that use index values

Len Brown
2009-03-28T04:33:51Z

From: Zhang Rui <rui.zhang@intel.com>

The input/output of _BQC/_BCL/_BCM control methods should be represented
by a number between 0 and 100, and can be thought of as a percentage.
But some buggy _BQC/_BCL/_BCM methods use the index values instead.
http://bugzilla.kernel.org/show_bug.cgi?id=12302
http://bugzilla.kernel.org/show_bug.cgi?id=12249
http://bugzilla.kernel.org/show_bug.cgi?id=12037

Add the functionality to support such kind of BIOSes in ACPI video driver.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Acked-by: Matthew Garrett <mjg59@srcf.ucam.org>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/acpi/video.c | 91 ++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 70 insertions(+), 21 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index dc84970..1f1625c 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -171,6 +171,9 @@ struct acpi_video_device_cap {
struct acpi_video_brightness_flags {
u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
u8 _BCL_reversed:1; /* _BCL package is in a reversed order*/
+ u8 _BCL_use_index:1; /* levels in _BCL are index values */
+ u8 _BCM_use_index:1; /* input of _BCM is an index value */
+ u8 _BQC_use_index:1; /* _BQC returns an index value */
};

struct acpi_video_device_brightness {
@@ -505,7 +508,8 @@ acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
device->brightness->curr = level;
for (state = 2; state < device->brightness->count; state++)
if (level == device->brightness->levels[state]) {
- device->backlight->props.brightness = state - 2;
+ if (device->backlight)
+ device->backlight->props.brightness = state - 2;
return 0;
}

@@ -523,6 +527,13 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
status = acpi_evaluate_integer(device->dev->handle, "_BQC",
NULL, level);
if (ACPI_SUCCESS(status)) {
+ if (device->brightness->flags._BQC_use_index) {
+ if (device->brightness->flags._BCL_reversed)
+ *level = device->brightness->count
+ - 3 - (*level);
+ *level = device->brightness->levels[*level + 2];
+
+ }
device->brightness->curr = *level;
return 0;
} else {
@@ -689,8 +700,10 @@ acpi_video_init_brightness(struct acpi_video_device *device)
{
union acpi_object *obj = NULL;
int i, max_level = 0, count = 0, level_ac_battery = 0;
+ unsigned long long level, level_old;
union acpi_object *o;
struct acpi_video_device_brightness *br = NULL;
+ int result = -EINVAL;

if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
@@ -704,13 +717,16 @@ acpi_video_init_brightness(struct acpi_video_device *device)
br = kzalloc(sizeof(*br), GFP_KERNEL);
if (!br) {
printk(KERN_ERR "can't allocate memory\n");
+ result = -ENOMEM;
goto out;
}

br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
GFP_KERNEL);
- if (!br->levels)
+ if (!br->levels) {
+ result = -ENOMEM;
goto out_free;
+ }

for (i = 0; i < obj->package.count; i++) {
o = (union acpi_object *)&obj->package.elements[i];
@@ -756,10 +772,55 @@ acpi_video_init_brightness(struct acpi_video_device *device)

br->count = count;
device->brightness = br;
+
+ /* Check the input/output of _BQC/_BCL/_BCM */
+ if ((max_level < 100) && (max_level <= (count - 2)))
+ br->flags._BCL_use_index = 1;
+
+ /*
+ * _BCM is always consistent with _BCL,
+ * at least for all the laptops we have ever seen.
+ */
+ br->flags._BCM_use_index = br->flags._BCL_use_index;
+
+ /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
+ br->curr = max_level;
+ result = acpi_video_device_lcd_get_level_current(device, &level_old);
+ if (result)
+ goto out_free_levels;
+
+ result = acpi_video_device_lcd_set_level(device, br->curr);
+ if (result)
+ goto out_free_levels;
+
+ result = acpi_video_device_lcd_get_level_current(device, &level);
+ if (result)
+ goto out_free_levels;
+
+ if ((level != level_old) && !br->flags._BCM_use_index) {
+ /* Note:
+ * This piece of code does not work correctly if the current
+ * brightness levels is 0.
+ * But I guess boxes that boot with such a dark screen are rare
+ * and no more code is needed to cover this specifial case.
+ */
+
+ if (level_ac_battery != 2) {
+ /*
+ * For now, we don't support the _BCL like this:
+ * 16, 15, 0, 1, 2, 3, ..., 14, 15, 16
+ * because we may mess up the index returned by _BQC.
+ * Plus: we have not got a box like this.
+ */
+ ACPI_ERROR((AE_INFO, "_BCL not supported\n"));
+ }
+ br->flags._BQC_use_index = 1;
+ }
+
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"found %d brightness levels\n", count - 2));
kfree(obj);
- return max_level;
+ return result;

out_free_levels:
kfree(br->levels);
@@ -768,7 +829,7 @@ out_free:
out:
device->brightness = NULL;
kfree(obj);
- return 0;
+ return result;
}

/*
@@ -785,7 +846,6 @@ out:
static void acpi_video_device_find_cap(struct acpi_video_device *device)
{
acpi_handle h_dummy1;
- u32 max_level = 0;

memset(&device->cap, 0, sizeof(device->cap));
@@ -814,13 +874,14 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
device->cap._DSS = 1;
}

- if (acpi_video_backlight_support())
- max_level = acpi_video_init_brightness(device);
-
- if (device->cap._BCL && device->cap._BCM && max_level > 0) {
+ if (acpi_video_backlight_support()) {
int result;
static int count = 0;
char *name;
+
+ result = acpi_video_init_brightness(device);
+ if (result)
+ return;
name = kzalloc(MAX_NAME_LEN, GFP_KERNEL);
if (!name)
return;
@@ -829,18 +890,6 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
device->backlight = backlight_device_register(name,
NULL, device, &acpi_backlight_ops);
device->backlight->props.max_brightness = device->brightness->count-3;
- /*
- * If there exists the _BQC object, the _BQC object will be
- * called to get the current backlight brightness. Otherwise
- * the brightness will be set to the maximum.
- */
- if (device->cap._BQC)
- device->backlight->props.brightness =
- acpi_video_get_brightness(device->backlight);
- else
- device->backlight->props.brightness =
- device->backlight->props.max_brightness;
- backlight_update_status(device->backlight);
kfree(name);

device->cdev = thermal_cooling_device_register("LCD",
--
1.6.0.6