diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 9 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/intel_panel.c | 17 |
2 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index ddbf18e..d44116b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -948,6 +948,15 @@ 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 + [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. + icn= [HW,ISDN] Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 04d79fd..d38a783 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); |