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Commit d8a2d0e0 authored by Zhenyu Wang's avatar Zhenyu Wang Committed by Eric Anholt
Browse files

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: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent 4bfe6b68

drivers/gpu/drm/i915/intel_hdmi.c

+22 −4
Original line number Diff line number Diff line
@@ -77,15 +77,33 @@ 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);



	/* 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)

{