From a95735569312f2ab0c80425e2cd1e5cb0b4e1870 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sun, 22 Aug 2010 13:18:16 +0100 Subject: drm/i915: Refactor panel backlight controls There were two instances of code to control the panel backlight and neither handled the complete set of device variations. Fixes: Bug 29716 - [GM965] Regression: Backlight resets to minimum when changing resolution https://bugs.freedesktop.org/show_bug.cgi?id=29716 And a bug on one of my PineView boxes which overflowed the backlight value. Incorporates part of a similar patch by Matthew Garrett that exposes a native Intel backlight controller. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/intel_panel.c | 109 +++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_panel.c') diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index e7f5299d9d5..30abe7afc94 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -30,6 +30,8 @@ #include "intel_drv.h" +#define PCI_LBPC 0xf4 /* legacy/combination backlight modes */ + void intel_fixed_panel_mode(struct drm_display_mode *fixed_mode, struct drm_display_mode *adjusted_mode) @@ -109,3 +111,110 @@ done: dev_priv->pch_pf_pos = (x << 16) | y; dev_priv->pch_pf_size = (width << 16) | height; } + +static int is_backlight_combination_mode(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + + if (IS_I965G(dev)) + return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE; + + if (IS_GEN2(dev)) + return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE; + + return 0; +} + +u32 intel_panel_get_max_backlight(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + u32 max; + + if (HAS_PCH_SPLIT(dev)) { + max = I915_READ(BLC_PWM_PCH_CTL2) >> 16; + } else { + max = I915_READ(BLC_PWM_CTL); + if (IS_PINEVIEW(dev)) { + max >>= 17; + } else { + max >>= 16; + if (!IS_I965G(dev)) + max &= ~1; + } + + if (is_backlight_combination_mode(dev)) + max *= 0xff; + } + + if (max == 0) { + /* XXX add code here to query mode clock or hardware clock + * and program max PWM appropriately. + */ + DRM_ERROR("fixme: max PWM is zero.\n"); + max = 1; + } + + DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max); + return max; +} + +u32 intel_panel_get_backlight(struct drm_device *dev) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + u32 val; + + if (HAS_PCH_SPLIT(dev)) { + val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; + } else { + val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; + if (IS_PINEVIEW(dev)) + val >>= 1; + + if (is_backlight_combination_mode(dev)){ + u8 lbpc; + + val &= ~1; + pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); + val *= lbpc; + val >>= 1; + } + } + + DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val); + return val; +} + +static void intel_pch_panel_set_backlight(struct drm_device *dev, u32 level) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + u32 val = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK; + I915_WRITE(BLC_PWM_CPU_CTL, val | level); +} + +void intel_panel_set_backlight(struct drm_device *dev, u32 level) +{ + struct drm_i915_private *dev_priv = dev->dev_private; + u32 tmp; + + DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level); + + if (HAS_PCH_SPLIT(dev)) + return intel_pch_panel_set_backlight(dev, level); + + if (is_backlight_combination_mode(dev)){ + u32 max = intel_panel_get_max_backlight(dev); + u8 lpbc; + + lpbc = level * 0xfe / max + 1; + level /= lpbc; + pci_write_config_byte(dev->pdev, PCI_LBPC, lpbc); + } + + tmp = I915_READ(BLC_PWM_CTL); + if (IS_PINEVIEW(dev)) { + tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1); + level <<= 1; + } else + tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK; + I915_WRITE(BLC_PWM_CTL, tmp | level); +} -- cgit v1.2.3