On 03/15/2013 06:10 PM, Danny Baumann wrote: > The value initially read via _BQC also needs to be offset by 2 to > compensate for the first 2 special items in _BCL. Introduce a helper > function that does the BQC-value-to-level conversion in order to not > needlessly duplicate code. > > Signed-off-by: Danny Baumann <dannybaumann@xxxxxx> > --- > drivers/acpi/video.c | 52 +++++++++++++++++++++++++++++++++------------------- > 1 file changed, 33 insertions(+), 19 deletions(-) > > diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c > index 5ef329a..8faea35 100644 > --- a/drivers/acpi/video.c > +++ b/drivers/acpi/video.c > @@ -450,6 +450,26 @@ static struct dmi_system_id video_dmi_table[] __initdata = { > {} > }; > > +static unsigned long long > +acpi_video_bqc_value_to_level(struct acpi_video_device *device, > + unsigned long long bqc_value) > +{ > + unsigned long long level; > + > + if (device->brightness->flags._BQC_use_index) { > + if (device->brightness->flags._BCL_reversed) > + bqc_value = device->brightness->count - 3 - bqc_value; > + > + level = device->brightness->levels[bqc_value + 2]; I don't understand this, what does the +2 have to do here? _BQC returned us an index, and then we should just convert it to level, why +2? The only explanation would be, for BIOS tables that return _BQC as index, they are indexing from the 3rd entry. Is it the case? If so, I think we need to put a comment here. > + } else { > + level = bqc_value; > + } > + > + level += bqc_offset_aml_bug_workaround; > + > + return level; > +} > + > static int > acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, > unsigned long long *level, int raw) > @@ -472,14 +492,8 @@ acpi_video_device_lcd_get_level_current(struct acpi_video_device *device, > return 0; > } > > - 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]; > + *level = acpi_video_bqc_value_to_level(device, *level); > > - } > - *level += bqc_offset_aml_bug_workaround; > for (i = 2; i < device->brightness->count; i++) > if (device->brightness->levels[i] == *level) { > device->brightness->curr = *level; > @@ -727,24 +741,24 @@ acpi_video_init_brightness(struct acpi_video_device *device) > > br->flags._BQC_use_index = (level == max_level ? 0 : 1); > > - if (!br->flags._BQC_use_index) { > - /* > - * 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 > - */ > - if (use_bios_initial_backlight) { ------------------------------------------------------------------- > + if (use_bios_initial_backlight) { > + if (!br->flags._BQC_use_index) { > + /* > + * 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. > + */ > for (i = 2; i < br->count; i++) > if (level_old == br->levels[i]) { > level = level_old; > break; > } > + } else { > + level = acpi_video_bqc_value_to_level(device, > + level_old); What about we convert the value to level first? if (use_bios_initial_backlight) { level = acpi_video_bqc_value_to_level(device, level_old); /* * 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(no matter it is a level, or an * index.) Set the backlight to max_level in this case. */ for (i = 2; i < br->count; i++) if (level == br->levels[i]) break; if (i == br->count) level = max_level; } Thanks, Aaron > } > - } else { > - if (br->flags._BCL_reversed) > - level_old = (br->count - 1) - level_old; > - level = br->levels[level_old]; > } > > set_level: > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html