The patch below does not apply to the 3.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 3f577573cd5482a32f85bd131e52f7cb4b9ac518 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@xxxxxxxxx>
Date: Thu, 25 Jul 2013 14:31:30 +0300
Subject: [PATCH] drm/i915: do not disable backlight on vgaswitcheroo switch
off
On muxed systems, the other vgaswitcheroo client may depend on i915 to
handle the backlight. We began switching off the backlight since
commit a261b246ebd552fd5d5a8ed84cc931bb821c427f
Author: Daniel Vetter <daniel.vetter@xxxxxxxx>
Date: Thu Jul 26 19:21:47 2012 +0200
drm/i915: disable all crtcs at suspend time
breaking backlight on discreet graphics in (some) muxed systems.
Keep the backlight on when the state is changed through vgaswitcheroo.
Note: The alternative would be to add a quirk table to achieve the same
based on system identifiers, but AFAICS it would asymptotically approach
effectively the same as this patch as more IDs are added, but with the
maintenance burden of the quirk table.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=55311
Tested-by: Fede <fedevx@xxxxxxxxx>
Tested-by: Aximab <laurent.debian@xxxxxxxxx>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59785
Tested-by: sfievet <sebastien.fievet@xxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 5063ead..5950888 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -518,6 +518,17 @@ void intel_panel_disable_backlight(struct drm_device *dev)
struct drm_i915_private *dev_priv = dev->dev_private;
unsigned long flags;
+ /*
+ * Do not disable backlight on the vgaswitcheroo path. When switching
+ * away from i915, the other client may depend on i915 to handle the
+ * backlight. This will leave the backlight on unnecessarily when
+ * another client is not activated.
+ */
+ if (dev->switch_power_state == DRM_SWITCH_POWER_CHANGING) {
+ DRM_DEBUG_DRIVER("Skipping backlight disable on vga switch\n");
+ return;
+ }
+
spin_lock_irqsave(&dev_priv->backlight.lock, flags);
dev_priv->backlight.enabled = false;
--
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