drm/i915: panel: invert brightness via quirk

commit 4dca20efb1a9c2efefc28ad2867e5d6c3f5e1955 upstream.

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>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d44116b..897f223 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -948,14 +948,19 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        i8k.restricted  [HW] Allow controlling fans only if SYS_ADMIN
                        capability is set.
 
-       i915.invert_brightness
+       i915.invert_brightness=
                        [DRM] Invert the sense of the variable that is used to
                        set the brightness of the panel backlight. Normally a
-                       value of 0 indicates backlight switched off, and the
-                       maximum value sets the backlight to maximum brightness.
-                       If this parameter is specified, a value of 0 sets the
-                       backlight to maximum brightness, and the maximum value
-                       switches the backlight off.
+                       brightness value of 0 indicates backlight switched off,
+                       and the maximum of the brightness value sets the backlight
+                       to maximum brightness. If this parameter is set to 0
+                       (default) and the machine requires it, or this parameter
+                       is set to 1, a brightness value of 0 sets the backlight
+                       to maximum brightness, and the maximum of the brightness
+                       value switches the backlight off.
+                       -1 -- never invert brightness
+                        0 -- machine default
+                        1 -- force brightness inversion
 
        icn=            [HW,ISDN]
                        Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 012a9d2..144d37c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -274,6 +274,7 @@ enum intel_pch {
 
 #define QUIRK_PIPEA_FORCE (1<<0)
 #define QUIRK_LVDS_SSC_DISABLE (1<<1)
+#define QUIRK_INVERT_BRIGHTNESS (1<<2)
 
 struct intel_fbdev;
 struct intel_fbc_work;

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 17961df..b096c0e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8831,6 +8831,15 @@ static void quirk_ssc_force_disable(struct drm_device *dev)
        dev_priv->quirks |= QUIRK_LVDS_SSC_DISABLE;
 }
 
+/*
+ * A machine may need to invert the panel backlight brightness value
+ */
+static void quirk_invert_brightness(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       dev_priv->quirks |= QUIRK_INVERT_BRIGHTNESS;
+}
+
 struct intel_quirk {
        int device;
        int subsystem_vendor;

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index d38a783..72b8949 100644 (file)
--- 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;