On Thursday 01 April 2010, Zhang Rui wrote:
> On Thu, 2010-04-01 at 09:34 +0800, Zhang Rui wrote:
> > On Thu, 2010-04-01 at 09:19 +0800, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rjw@xxxxxxx>
> > >
> > > On Acer Ferrari One, when _BQC is invoked for the first time, the
> > > minimum brightness is returned, so the ACPI video drivers sets the
> > > minimum brightness on boot. This is not desirable, so use the
> > > following rule:
> > > If _BQC initially returns an invalid value or the minimum
> > > brightness, use either the brightness level supposed to be
> > > used on AC power, or the brightness level supposed to be
> > > used on battery, depending on whether or not the system is
> > > on AC power. If these values are not exported by the BIOS,
> > > use the maximum brightness level.
> > >
> > > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> > > ---
> > > drivers/acpi/video.c | 26 +++++++++++++++++++++++---
> > > 1 file changed, 23 insertions(+), 3 deletions(-)
> > >
> > > Index: linux-2.6/drivers/acpi/video.c
> > > ===================================================================
> > > --- linux-2.6.orig/drivers/acpi/video.c
> > > +++ linux-2.6/drivers/acpi/video.c
> > > @@ -44,6 +44,7 @@
> > > #include <acpi/acpi_bus.h>
> > > #include <acpi/acpi_drivers.h>
> > > #include <linux/suspend.h>
> > > +#include <linux/power_supply.h>
> > >
> > > #define PREFIX "ACPI: "
> > >
> > > @@ -920,11 +928,20 @@ acpi_video_init_brightness(struct acpi_v
> > > * Set the backlight to the initial state.
> > > * On some buggy laptops, _BQC returns an uninitialized value
> > > * when invoked for the first time, i.e. level_old is invalid.
> > > - * set the backlight to max_level in this case
> > > + * On some other systems _BQC returns the minimum brightness
> > > + * when invoked for the first time, which also usually is
> > > + * undesirable. In that cases use the "AC power" value if on AC
> > > + * power or the "battery" value otherwise. If these vaules are
> > > + * not exported, use max_level.
> > > */
> > > - for (i = 2; i < br->count; i++)
> > > - if (level_old == br->levels[i])
> > > + for (i = 3; i < br->count; i++)
> > > + if (level_old == br->levels[i]) {
> > > level = level_old;
> > > + goto set_level;
> > > + }
> > > + if (!br->flags._BCL_no_ac_battery_levels)
> > > + level = power_supply_is_system_supplied() ?
> > > +
> > > br->levels[0] : br->levels[1];
> >
> > this doesn't work currently.
> > br->levels[0] and br->levels[1] doesn't equal the "AC power" value and
> > "Battery" value, because the "AC power" and "Battery" value is not
> > exported by many BIOS at all.
But if the BIOS doesn't export these values,
br->flags._BCL_no_ac_battery_levels will be true, won't it?
> I mean, for these laptops, br->levels[0] and br->levels[1] equals the
> first and second elements in _BCL package.
> But we can not use them as the "AC power" and "Battery" value.
In that cases the if (!br->flags._BCL_no_ac_battery_levels) condition won't
be satisfied.
On a second thought, though, something like this also works and is simpler.
Rafael
---
From: Rafael J. Wysocki <rjw@xxxxxxx>
Subject: ACPI / Video: Fix initial brightness problem on Acer Ferrari One (v. 2)
On Acer Ferrari One, when _BQC is invoked for the first time, the
minimum brightness is returned, so the ACPI video drivers sets the
minimum brightness on boot. This is not desirable, so use the
following rule:
Set brightness to either the level supposed to be used on
AC power, or the brightness level supposed to be used on
battery, depending on whether or not the system is on AC
power. If these values are not exported by the BIOS, use the
brightness level initially returned by _BQC. If that value
is invalid, use the maximum brightness level.
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
drivers/acpi/video.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
Index: linux-2.6/drivers/acpi/video.c
===================================================================
--- linux-2.6.orig/drivers/acpi/video.c
+++ linux-2.6/drivers/acpi/video.c
@@ -44,6 +44,7 @@
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <linux/suspend.h>
+#include <linux/power_supply.h>
#define PREFIX "ACPI: "
@@ -915,6 +916,18 @@ acpi_video_init_brightness(struct acpi_v
br->flags._BQC_use_index = (level == max_level ? 0 : 1);
+ /*
+ * Set brightness to the "AC power" value if on AC power or to the
+ * "battery" value otherwise. If these vaules are not exported, try
+ * to use the value returned by the initial _BQC and fall back to
+ * max_level.
+ */
+ if (!br->flags._BCL_no_ac_battery_levels) {
+ level = power_supply_is_system_supplied() ?
+ br->levels[0] : br->levels[1];
+ goto set_level;
+ }
+
if (!br->flags._BQC_use_index) {
/*
* Set the backlight to the initial state.
@@ -930,7 +943,8 @@ acpi_video_init_brightness(struct acpi_v
if (br->flags._BCL_reversed)
level_old = (br->count - 1) - level_old;
- level = br->levels[level_old];
+ level = level_old >= 0 && level_old < br->count ?
+ br->levels[level_old] : max_level;
set_level:
result = acpi_video_device_lcd_set_level(device, level);
--
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