Dear all,
On a custom board I have a simple DPI panel. Panel's backlight is drive with an I2C led driver (PCA9632). led-backlight driver is sued to manage this as a backlight.
When using brightness-levels and default-brightness-level the backlight stay turned-off even if manually trying to set a different index value to brightness through sysfs.
I traced this issue as follow: When led_bl_update_status() is called the brightness value is returned from backlight_get_brightness() which call backlight_is_blank(). In my case backlight_is_blank() return true due to props.power = FB_BLANK_POWERDOWN which is != FB_BLANK_UNBLANK.
I traced why at startup props.power is FB_BLANK_POWERDOWN and found that in led_bl_probe() when a default brightness is set (>0) props.power is set to FB_BLANK_POWERDOWN which seems incorrect to me.
I made the small change below and default brightness is correctly used at startup. I am not really sure this is an issue and if my change is correct or if I am doing something incorrect somewhere else. So I first would like to get your opinion on this and if correct will send a patch.
Many thanks in advance Patrick
diff --git a/drivers/video/backlight/led_bl.c b/drivers/video/backlight/led_bl.c --- a/drivers/video/backlight/led_bl.c +++ b/drivers/video/backlight/led_bl.c @@ -200,7 +200,7 @@ static int led_bl_probe(struct platform_device *pdev) props.type = BACKLIGHT_RAW; props.max_brightness = priv->max_brightness; props.brightness = priv->default_brightness; - props.power = (priv->default_brightness > 0) ? FB_BLANK_POWERDOWN : + props.power = (priv->default_brightness == 0) ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK; priv->bl_dev = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, priv, &led_bl_ops, &props);