From: Zhang Rui <rui.zhang@xxxxxxxxx> In the current code, for a box with an indexed _BQC method, we 1. get the current brightness level by evaluating _BQC 2. set the value gotten in step 1 to _BCM 3. get the current brightness level again 4. set the _BQC_use_index flag if the results gotten in step 1 and in step 3 don't equal. But this logic doesn't work actually, because the _BQC_use_index is not set when acpi_video_device_lcd_set_level is invoked. This results in a failure in step 2. http://bugzilla.kernel.org/show_bug.cgi?id=12249#c83 Now, we set the _BQC_use_index flag after invoking _BQC for the first time. And reevaluate the _BQC to get the correct brightness level. Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/video.c | 43 ++++++++++++++++++++++--------------------- 1 files changed, 22 insertions(+), 21 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index cd4fb75..346277f 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -807,12 +807,19 @@ acpi_video_init_brightness(struct acpi_video_device *device) br->flags._BCM_use_index = br->flags._BCL_use_index; /* _BQC uses INDEX while _BCL uses VALUE in some laptops */ - br->curr = max_level; + br->curr = level_old = max_level; + + if (!device->cap._BQC) + goto set_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); + /* + * Set the level to maximum and check if _BQC uses indexed value + */ + result = acpi_video_device_lcd_set_level(device, max_level); if (result) goto out_free_levels; @@ -820,25 +827,19 @@ acpi_video_init_brightness(struct acpi_video_device *device) 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; - } + br->flags._BQC_use_index = (level == max_level ? 0 : 1); + + if (!br->flags._BQC_use_index) + goto set_level; + + if (br->flags._BCL_reversed) + level_old = (br->count - 1) - level_old; + level_old = br->levels[level_old]; + +set_level: + result = acpi_video_device_lcd_set_level(device, level_old); + if (result) + goto out_free_levels; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "found %d brightness levels\n", count - 2)); -- 1.6.0.6 -- 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
