[PATCH 3.4 171/214] drm/i915: panel: invert brightness via quirk

Greg Kroah-Hartman
2014-06-05T04:34:32Z

From: Carsten Emde <C.Emde@osadl.org>

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>
[wml: Backported to 3.4:
- Adjust context
- one more flag QUIRK_NO_PCH_PWM_ENABLE]
Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Documentation/kernel-parameters.txt | 17 +++++++++++------
drivers/gpu/drm/i915/i915_drv.h | 3 ++-
drivers/gpu/drm/i915/intel_display.c | 9 +++++++++
drivers/gpu/drm/i915/intel_panel.c | 15 +++++++++++----
4 files changed, 33 insertions(+), 11 deletions(-)

--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -993,14 +993,19 @@ bytes respectively. Such letter suffixes
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>]]]
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -296,7 +296,8 @@ enum intel_pch {

#define QUIRK_PIPEA_FORCE (1<<0)
#define QUIRK_LVDS_SSC_DISABLE (1<<1)
-#define QUIRK_NO_PCH_PWM_ENABLE (1<<2)
+#define QUIRK_INVERT_BRIGHTNESS (1<<2)
+#define QUIRK_NO_PCH_PWM_ENABLE (1<<3)

struct intel_fbdev;
struct intel_fbc_work;
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9200,6 +9200,15 @@ static void quirk_no_pcm_pwm_enable(stru
DRM_INFO("applying no-PCH_PWM_ENABLE quirk\n");
}

+/*
+ * 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;
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -190,15 +190,22 @@ u32 intel_panel_get_max_backlight(struct
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;