Re: [PATCH v3 04/11] backlight: Implement fbdev tracking with blank state from event
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From: Daniel Thompson <danielt@kernel.org>
Date: 2025-03-18 09:05:55
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dri-devel, linux-leds
On Thu, Mar 06, 2025 at 03:05:46PM +0100, Thomas Zimmermann wrote:
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>
Reviewed-by: Daniel Thompson (RISCstar) <danielt@kernel.org> Daniel.