From 04b38670cf46c096705f24e92a8747d1ab89e53c Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Wed, 16 Nov 2011 10:58:03 +0100
Subject: [PATCH] drm/i915: Fix inconsistent backlight level during disabled
When the brightness property is inquired while the backlight is disabled,
the driver returns a wrong value (zero) because it probes the value after
the backlight was turned off. This caused a black screen even after the
backlight is enabled again. It should return the internal backlight_level
instead, so that it won't be influenced by the backlight-enable state.
BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=41926
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/872652
Tested-by: Kamal Mostafa <kamal@canonical.com>
Cc: Alex Davis <alex14641@yahoo.com>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Keith Packard <keithp@keithp.com>
---
drivers/gpu/drm/i915/intel_panel.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 499d4c0dbeeb..21f60b7d69a3 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -326,7 +326,8 @@ static int intel_panel_update_status(struct backlight_device *bd)
static int intel_panel_get_brightness(struct backlight_device *bd)
{
struct drm_device *dev = bl_get_data(bd);
- return intel_panel_get_backlight(dev);
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ return dev_priv->backlight_level;
}
static const struct backlight_ops intel_panel_bl_ops = {
--
2.34.1