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* [PATCH 1/6] backlight: Nuke unused backlight.props.state states
@ 2018-04-25 17:42 Daniel Vetter
  2018-04-25 17:42 ` [PATCH 2/6] backlight/generic-bl: remove DRIVER1 state Daniel Vetter
                   ` (7 more replies)
  0 siblings, 8 replies; 24+ messages in thread
From: Daniel Vetter @ 2018-04-25 17:42 UTC (permalink / raw)
  To: DRI Development, LKML
  Cc: Daniel Vetter, Lee Jones, Daniel Thompson, Jingoo Han,
	Meghana Madhyastha, Daniel Vetter

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
- 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 <lee.jones@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Meghana Madhyastha <meghana.madhyastha@gmail.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 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 */
 
 };
-- 
2.17.0

^ permalink raw reply	[flat|nested] 24+ messages in thread
* [PATCH 1/6] backlight: Nuke unused backlight.props.state states
@ 2018-01-17 14:01 Daniel Vetter
  2018-01-17 14:01 ` [PATCH 2/6] backlight/generic-bl: remove DRIVER1 state Daniel Vetter
  0 siblings, 1 reply; 24+ messages in thread
From: Daniel Vetter @ 2018-01-17 14:01 UTC (permalink / raw)
  To: DRI Development
  Cc: LKML, Daniel Vetter, Lee Jones, Daniel Thompson, Jingoo Han,
	Meghana Madhyastha, Daniel Vetter

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
- 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 <lee.jones@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Meghana Madhyastha <meghana.madhyastha@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 include/linux/backlight.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index af7003548593..9776edb0ff06 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 */
 
 };
-- 
2.15.1

^ permalink raw reply	[flat|nested] 24+ messages in thread

end of thread, other threads:[~2018-04-30 12:27 UTC | newest]

Thread overview: 24+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-25 17:42 [PATCH 1/6] backlight: Nuke unused backlight.props.state states Daniel Vetter
2018-04-25 17:42 ` [PATCH 2/6] backlight/generic-bl: remove DRIVER1 state Daniel Vetter
2018-04-30 10:21   ` Jani Nikula
2018-04-25 17:42 ` [PATCH 3/6] backlight/pandora: Stop using BL_CORE_DRIVER1 Daniel Vetter
2018-04-30 10:22   ` Jani Nikula
2018-04-25 17:42 ` [PATCH 4/6] staging/fbtft: " Daniel Vetter
2018-04-30  9:54   ` Lee Jones
2018-04-30 10:59     ` Greg KH
2018-04-30 10:22   ` Jani Nikula
2018-04-25 17:42 ` [PATCH 5/6] backlight: Also nuke BL_CORE_DRIVER1 Daniel Vetter
2018-04-30 10:24   ` Jani Nikula
2018-04-30 12:14     ` Lee Jones
2018-04-25 17:42 ` [PATCH 6/6] MAINTAINERS: add dri-devel for backlight subsystem patches Daniel Vetter
2018-04-25 19:43   ` Jingoo Han
2018-04-25 19:42 ` [PATCH 1/6] backlight: Nuke unused backlight.props.state states Jingoo Han
2018-04-30 10:21 ` Jani Nikula
2018-04-30 12:27 ` Lee Jones
  -- strict thread matches above, loose matches on Subject: below --
2018-01-17 14:01 Daniel Vetter
2018-01-17 14:01 ` [PATCH 2/6] backlight/generic-bl: remove DRIVER1 state Daniel Vetter
2018-01-17 14:36   ` Emil Velikov
2018-01-17 16:37     ` Daniel Thompson
2018-01-18 13:08       ` Emil Velikov
2018-01-17 16:44   ` Daniel Thompson
2018-01-17 17:13     ` Daniel Vetter
2018-01-18  9:20       ` Daniel Thompson

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