From d8a2d0e00c0d5a0d55e14b884bff034205015e51 Mon Sep 17 00:00:00 2001 From: Zhenyu Wang Date: Mon, 2 Nov 2009 07:52:30 +0000 Subject: [PATCH] drm/i915: HDMI hardware workaround for Ironlake This brings some hardware workaround for HDMI port on PCH (Ibex Peak), which fixes unstable issues like during rotation. Signed-off-by: Zhenyu Wang Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/intel_hdmi.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c index 663ab6d..c33451a 100644 --- a/drivers/gpu/drm/i915/intel_hdmi.c +++ b/drivers/gpu/drm/i915/intel_hdmi.c @@ -77,14 +77,32 @@ static void intel_hdmi_dpms(struct drm_encoder *encoder, int mode) struct intel_hdmi_priv *hdmi_priv = intel_output->dev_priv; u32 temp; - if (mode != DRM_MODE_DPMS_ON) { - temp = I915_READ(hdmi_priv->sdvox_reg); + temp = I915_READ(hdmi_priv->sdvox_reg); + + /* HW workaround, need to toggle enable bit off and on for 12bpc, but + * we do this anyway which shows more stable in testing. + */ + if (IS_IGDNG(dev)) { I915_WRITE(hdmi_priv->sdvox_reg, temp & ~SDVO_ENABLE); + POSTING_READ(hdmi_priv->sdvox_reg); + } + + if (mode != DRM_MODE_DPMS_ON) { + temp &= ~SDVO_ENABLE; } else { - temp = I915_READ(hdmi_priv->sdvox_reg); - I915_WRITE(hdmi_priv->sdvox_reg, temp | SDVO_ENABLE); + temp |= SDVO_ENABLE; } + + I915_WRITE(hdmi_priv->sdvox_reg, temp); POSTING_READ(hdmi_priv->sdvox_reg); + + /* HW workaround, need to write this twice for issue that may result + * in first write getting masked. + */ + if (IS_IGDNG(dev)) { + I915_WRITE(hdmi_priv->sdvox_reg, temp); + POSTING_READ(hdmi_priv->sdvox_reg); + } } static void intel_hdmi_save(struct drm_connector *connector) -- 2.7.4