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Commit 5bddd17f authored by Eric Anholt's avatar Eric Anholt Committed by Chris Wilson
Browse files

drm/i915: Apply a workaround for transitioning from DP on pipe B to HDMI. 



This workaround only applies to Ironlake.

Signed-off-by: default avatarEric Anholt <eric@anholt.net>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
parent 220cad3c

drivers/gpu/drm/i915/intel_dp.c

+21 −0
Original line number Diff line number Diff line
@@ -1374,6 +1374,7 @@ intel_dp_link_down(struct intel_dp *intel_dp) 
{

	struct drm_device *dev = intel_dp->base.base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	struct intel_crtc *intel_crtc = to_intel_crtc(intel_dp->base.base.crtc);

	uint32_t DP = intel_dp->DP;



	DRM_DEBUG_KMS("\n");
@@ -1398,6 +1399,26 @@ intel_dp_link_down(struct intel_dp *intel_dp) 


	if (is_edp(intel_dp))

		DP |= DP_LINK_TRAIN_OFF;



	if (!HAS_PCH_CPT(dev) && (DP & DP_PIPEB_SELECT)) {

		/* Hardware workaround: leaving our transcoder select

		 * set to transcoder B while it's off will prevent the

		 * corresponding HDMI output on transcoder A.

		 *

		 * Combine this with another hardware workaround:

		 * transcoder select bit can only be cleared while the

		 * port is enabled.

		 */

		DP &= ~DP_PIPEB_SELECT;

		I915_WRITE(intel_dp->output_reg, DP);



		/* Changes to enable or select take place the vblank

		 * after being written.

		 */

		intel_wait_for_vblank(intel_dp->base.base.dev,

				      intel_crtc->pipe);

	}



	I915_WRITE(intel_dp->output_reg, DP & ~DP_PORT_EN);

	POSTING_READ(intel_dp->output_reg);

}