[PATCH v3 04/11] backlight: Implement fbdev tracking with blank state from event
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STALE583d
SUPERSEDED
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: 2025-03-06 14:13:25
Also in:
dri-devel, linux-leds
Subsystem:
backlight class/subsystem, framebuffer layer, the rest · Maintainers:
Lee Jones, Daniel Thompson, Jingoo Han, Helge Deller, Linus Torvalds
Revision v3 of 4 in this series.
Revisions (4)
- rfc [diff vs current]
- v2 [diff vs current]
- v3 current
- v4 [diff vs current]
Look at the blank state provided by FB_EVENT_BLANK to determine whether to enable or disable a backlight. Remove the tracking fields from struct backlight_device. Tracking requires three variables, fb_on, prev_fb_on and the backlight's use_count. If fb_on is true, the display has been unblanked. The backlight needs to be enabled if the display was blanked before (i.e., prev_fb_on is false) or if use_count is still at 0. If fb_on is false, the display has been blanked. In this case, the backlight has to be disabled was unblanked before and the backlight's use_count is greater than 0. This change removes fbdev state tracking from blacklight. All the backlight requires it its own use counter and information about changes to the display. Removing fbdev internals makes backlight drivers easier to integrate into other display drivers, such as DRM. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> --- drivers/video/backlight/backlight.c | 14 +++++++------- include/linux/backlight.h | 10 +--------- 2 files changed, 8 insertions(+), 16 deletions(-)
diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
index f699e5827ccb..bb01f57c4683 100644
--- a/drivers/video/backlight/backlight.c
+++ b/drivers/video/backlight/backlight.c@@ -98,9 +98,9 @@ static int fb_notifier_callback(struct notifier_block *self, struct backlight_device *bd; struct fb_event *evdata = data; struct fb_info *info = evdata->info; + const int *fb_blank = evdata->data; struct backlight_device *fb_bd = fb_bl_device(info); - int node = info->node; - int fb_blank = 0; + bool fb_on, prev_fb_on; /* If we aren't interested in this event, skip it immediately ... */ if (event != FB_EVENT_BLANK)
@@ -116,15 +116,15 @@ static int fb_notifier_callback(struct notifier_block *self, if (fb_bd && fb_bd != bd) goto out; - fb_blank = *(int *)evdata->data; - if (fb_blank == FB_BLANK_UNBLANK && !bd->fb_bl_on[node]) { - bd->fb_bl_on[node] = true; + fb_on = fb_blank[0] == FB_BLANK_UNBLANK; + prev_fb_on = fb_blank[1] == FB_BLANK_UNBLANK; + + if (fb_on && (!prev_fb_on || !bd->use_count)) { if (!bd->use_count++) { bd->props.state &= ~BL_CORE_FBBLANK; backlight_update_status(bd); } - } else if (fb_blank != FB_BLANK_UNBLANK && bd->fb_bl_on[node]) { - bd->fb_bl_on[node] = false; + } else if (!fb_on && prev_fb_on && bd->use_count) { if (!(--bd->use_count)) { bd->props.state |= BL_CORE_FBBLANK; backlight_update_status(bd);
diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index f5652e5a9060..03723a5478f8 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h@@ -294,15 +294,7 @@ struct backlight_device { struct device dev; /** - * @fb_bl_on: The state of individual fbdev's. - * - * Multiple fbdev's may share one backlight device. The fb_bl_on - * records the state of the individual fbdev. - */ - bool fb_bl_on[FB_MAX]; - - /** - * @use_count: The number of uses of fb_bl_on. + * @use_count: The number of unblanked displays. */ int use_count; };
--
2.48.1