From c4d81671920a083c8a81188ea6d25fe6132599e1 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Wed, 24 Jul 2013 13:55:34 +0300 Subject: [PATCH] drm/i915: do not disable backlight on vgaswitcheroo switch off Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Cc: Jani Nikula 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 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 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59785 Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_panel.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 80bea1d..69059ac 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -512,6 +512,17 @@ 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; -- 1.7.9.5