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Subject[PATCH 1/6] backlight: Nuke unused backlight.props.state states
The backlight power state handling is supremely confusing. We have:
- props.power, using FB_BLANK_* defines
- props.fb_blank, using the same, but deprecated int favour of
- props.state, using the BL_CORE_* defines
- and finally a bunch of backlight drivers treat brightness == 0 as
off. But of course not all of them.

This is way too much confusion to fix in a simple patch, but at least
prevent more hilarity from spreading by removing the unused BL_CORE_*
defines. I have no idea why exactly anyone would need that.

Wrt the ideal state, we really just want a boolean state. The 4 power
saving states that the fbdev subsystem uses are overkill in todays hw
(this was only relevant for VGA and similar analog circuits like
TV-out), the new drm atomic modeset api simplified even the uapi to a
simple bool. And there was never a valid technical reason to have the
intermediate fbdev power states for backlights (those really only can
be either off or on).

Cleanup motivated by Meghana's questions about all this.

Cc: Lee Jones <>
Cc: Daniel Thompson <>
Cc: Jingoo Han <>
Cc: Meghana Madhyastha <>
Acked-by: Daniel Thompson <>
Signed-off-by: Daniel Vetter <>
include/linux/backlight.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 2baab6f3861d..1db67662bfcb 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -84,9 +84,6 @@ struct backlight_properties {

#define BL_CORE_SUSPENDED (1 << 0) /* backlight is suspended */
#define BL_CORE_FBBLANK (1 << 1) /* backlight is under an fb blank event */
-#define BL_CORE_DRIVER4 (1 << 28) /* reserved for driver specific use */
-#define BL_CORE_DRIVER3 (1 << 29) /* reserved for driver specific use */
-#define BL_CORE_DRIVER2 (1 << 30) /* reserved for driver specific use */
#define BL_CORE_DRIVER1 (1 << 31) /* reserved for driver specific use */

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