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-rw-r--r--drivers/gpu/drm/i915/intel_panel.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 230a141dbea3..c4b3f349af69 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -28,6 +28,7 @@
* Chris Wilson <chris@chris-wilson.co.uk>
*/
+#include <linux/moduleparam.h>
#include "intel_drv.h"
#define PCI_LBPC 0xf4 /* legacy/combination backlight modes */
@@ -191,6 +192,20 @@ 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 "
+ "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);
+static u32 intel_panel_compute_brightness(struct drm_device *dev, u32 val)
+{
+ if (i915_panel_invert_brightness)
+ return intel_panel_get_max_backlight(dev) - val;
+
+ return val;
+}
+
u32 intel_panel_get_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -211,6 +226,7 @@ u32 intel_panel_get_backlight(struct drm_device *dev)
}
}
+ val = intel_panel_compute_brightness(dev, val);
DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
return val;
}
@@ -228,6 +244,7 @@ static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level
u32 tmp;
DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
+ level = intel_panel_compute_brightness(dev, level);
if (HAS_PCH_SPLIT(dev))
return intel_pch_panel_set_backlight(dev, level);