From: pgeiem <pgeiem@protonmail.com>
To: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
Subject: [led-backlight] default-brightness-level issue
Date: Fri, 23 Apr 2021 13:04:23 +0000 [thread overview]
Message-ID: <e_WDxLKZ_lxATxDaTMkr5jVLhIs2O0NQOSd-Inff7IMEU7i1QyX_BTldVJZgP_Yb-lgzTmpPxni_1YCQmhyGmi_ahjHbG5aCNtUngw35g0M=@protonmail.com> (raw)
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);
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next reply other threads:[~2021-04-23 13:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 13:04 pgeiem [this message]
2021-04-29 11:00 ` [led-backlight] default-brightness-level issue Daniel Thompson
2021-04-29 11:31 ` pgeiem
2021-04-29 12:07 ` Daniel Thompson
2021-05-04 7:10 ` pgeiem
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