From ba156ef02a136ce8c045e7d9860f45b9cc6341d8 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Sun, 21 Nov 2021 12:00:32 +0100
Subject: drm/i915/backlight: Make ext_pwm_disable_backlight() call
intel_backlight_set_pwm_level()
Git-commit: 637088a21e204b129a03dbd59bc0cd80d0292651
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
At least the Bay Trail LPSS PWM controller used with DSI panels on many
Bay Trail tablets seems to leave the PWM pin in whatever state it was
(high or low) ATM that the PWM gets disabled. Combined with some panels
not having a separate backlight-enable pin this leads to the backlight
sometimes staying on while it should not (when the pin was high during
PWM-disabling).
First calling intel_backlight_set_pwm_level() will ensure that the pin
is always low (or high for inverted brightness panels) since the passed
in duty-cycle is 0% (or 100%) when the PWM gets disabled fixing the
backlight sometimes staying on.
With the exception of ext_pwm_disable_backlight() all other
foo_disable_backlight() functions call intel_backlight_set_pwm_level()
already before disabling the backlight, so this change also aligns
ext_pwm_disable_backlight() with all the other disable() functions.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211121110032.4720-2-hdegoede@redhat.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_backlight.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index 9523411cddd8..2db3b792aca6 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -433,6 +433,8 @@ static void ext_pwm_disable_backlight(const struct drm_connector_state *old_conn
struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
struct intel_panel *panel = &connector->panel;
+ intel_backlight_set_pwm_level(old_conn_state, level);
+
panel->backlight.pwm_state.enabled = false;
pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
}
--
2.38.1