drm/i915: panel: invert brightness via quirk

A machine may need to invert the panel backlight brightness value. This
patch adds the infrastructure for a quirk to do so.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index c4b3f349af69..7998ca6f594f 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -192,15 +192,22 @@ u32 intel_panel_get_max_backlight(struct drm_device *dev)
         return max;
 }
 
-static bool i915_panel_invert_brightness;
-MODULE_PARM_DESC(invert_brightness, "Invert backlight brightness, please "
+static int i915_panel_invert_brightness;
+MODULE_PARM_DESC(invert_brightness, "Invert backlight brightness "
+        "(-1 force normal, 0 machine defaults, 1 force inversion), please "
         "report PCI device ID, subsystem vendor and subsystem device ID "
         "to dri-devel@lists.freedesktop.org, if your machine needs it. "
         "It will then be included in an upcoming module version.");
-module_param_named(invert_brightness, i915_panel_invert_brightness, bool, 0600);
+module_param_named(invert_brightness, i915_panel_invert_brightness, int, 0600);
 static u32 intel_panel_compute_brightness(struct drm_device *dev, u32 val)
 {
-        if (i915_panel_invert_brightness)
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        if (i915_panel_invert_brightness < 0)
+                return val;
+
+        if (i915_panel_invert_brightness > 0 ||
+            dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS)
                 return intel_panel_get_max_backlight(dev) - val;
 
         return val;