From 0b0b053a3949f5c467c3b3ba135d4c161f9fbd00 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 23 Nov 2010 09:45:50 +0000 Subject: drm/i915/panel: Restore saved value of BLC_PWM_CTL After a GPU reset, the backlight controller registers may be also reset to 0. In that case we should restore those to the original values programmed by the BIOS. Note that we still lack the code to handle the case where the BIOS failed to program those registers at all... Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/intel_panel.c | 52 ++++++++++++++++++++++++++++++-------- 1 file changed, 42 insertions(+), 10 deletions(-) (limited to 'drivers/gpu/drm/i915') diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 92ff8f38527..7350ec2515c 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -125,15 +125,55 @@ static int is_backlight_combination_mode(struct drm_device *dev) return 0; } +static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv) +{ + u32 val; + + /* Restore the CTL value if it lost, e.g. GPU reset */ + + if (HAS_PCH_SPLIT(dev_priv->dev)) { + val = I915_READ(BLC_PWM_PCH_CTL2); + if (dev_priv->saveBLC_PWM_CTL2 == 0) { + dev_priv->saveBLC_PWM_CTL2 = val; + } else if (val == 0) { + I915_WRITE(BLC_PWM_PCH_CTL2, + dev_priv->saveBLC_PWM_CTL); + val = dev_priv->saveBLC_PWM_CTL; + } + } else { + val = I915_READ(BLC_PWM_CTL); + if (dev_priv->saveBLC_PWM_CTL == 0) { + dev_priv->saveBLC_PWM_CTL = val; + dev_priv->saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_CTL2); + } else if (val == 0) { + I915_WRITE(BLC_PWM_CTL, + dev_priv->saveBLC_PWM_CTL); + I915_WRITE(BLC_PWM_CTL2, + dev_priv->saveBLC_PWM_CTL2); + val = dev_priv->saveBLC_PWM_CTL; + } + } + + return val; +} + u32 intel_panel_get_max_backlight(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; u32 max; + max = i915_read_blc_pwm_ctl(dev_priv); + if (max == 0) { + /* XXX add code here to query mode clock or hardware clock + * and program max PWM appropriately. + */ + printk_once(KERN_WARNING "fixme: max PWM is zero.\n"); + return 1; + } + if (HAS_PCH_SPLIT(dev)) { - max = I915_READ(BLC_PWM_PCH_CTL2) >> 16; + max >>= 16; } else { - max = I915_READ(BLC_PWM_CTL); if (IS_PINEVIEW(dev)) { max >>= 17; } else { @@ -146,14 +186,6 @@ u32 intel_panel_get_max_backlight(struct drm_device *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; } -- cgit v1.2.3