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Commit 0767935e authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/i915: robustify edp_pll_on/off 



With the previous patch to clean up where exactly these two functions
are getting called, this patch can tackle the enable/disable code
itself:

- WARN if the port enable bit is in the wrong state or if the edp pll
  bit is in the wrong state, just for paranoia's sake.
- Don't disable the edp pll harder in the modeset functions just for
  fun.
- Don't set the edp pll enable flag in intel_dp->DP in modeset, do
  that while changing the actual hw state. We do the same with the
  actual port enable bit, so this is a bit more consistent.
- Track the current DP register value when setting things up and add
  some comments how intel_dp->DP is used in the disable code.

v2: Be more careful with resetting intel_dp->DP - otherwise dpms
off->on will fail spectacularly, becuase we enable the eDP port when
we should only enable the eDP pll.

Reviewed-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-Off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 2bd2ad64

drivers/gpu/drm/i915/intel_dp.c

+18 −11
Original line number Diff line number Diff line
@@ -887,7 +887,6 @@ intel_dp_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode, 
		intel_dp->DP |= intel_crtc->pipe << 29;



		/* don't miss out required setting for eDP */

		intel_dp->DP |= DP_PLL_ENABLE;

		if (adjusted_mode->clock < 200000)

			intel_dp->DP |= DP_PLL_FREQ_160MHZ;

		else
@@ -909,7 +908,6 @@ intel_dp_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode, 


		if (is_cpu_edp(intel_dp)) {

			/* don't miss out required setting for eDP */

			intel_dp->DP |= DP_PLL_ENABLE;

			if (adjusted_mode->clock < 200000)

				intel_dp->DP |= DP_PLL_FREQ_160MHZ;

			else
@@ -1192,8 +1190,15 @@ static void ironlake_edp_pll_on(struct intel_dp *intel_dp) 


	DRM_DEBUG_KMS("\n");

	dpa_ctl = I915_READ(DP_A);

	dpa_ctl |= DP_PLL_ENABLE;

	I915_WRITE(DP_A, dpa_ctl);

	WARN(dpa_ctl & DP_PLL_ENABLE, "dp pll on, should be off\n");

	WARN(dpa_ctl & DP_PORT_EN, "dp port still on, should be off\n");



	/* We don't adjust intel_dp->DP while tearing down the link, to

	 * facilitate link retraining (e.g. after hotplug). Hence clear all

	 * enable bits here to ensure that we don't enable too much. */

	intel_dp->DP &= ~(DP_PORT_EN | DP_AUDIO_OUTPUT_ENABLE);

	intel_dp->DP |= DP_PLL_ENABLE;

	I915_WRITE(DP_A, intel_dp->DP);

	POSTING_READ(DP_A);

	udelay(200);

}
@@ -1209,6 +1214,13 @@ static void ironlake_edp_pll_off(struct intel_dp *intel_dp) 
			     to_intel_crtc(crtc)->pipe);



	dpa_ctl = I915_READ(DP_A);

	WARN((dpa_ctl & DP_PLL_ENABLE) == 0,

	     "dp pll off, should be on\n");

	WARN(dpa_ctl & DP_PORT_EN, "dp port still on, should be off\n");



	/* We can't rely on the value tracked for the DP register in

	 * intel_dp->DP because link_down must not change that (otherwise link

	 * re-training will fail. */

	dpa_ctl &= ~DP_PLL_ENABLE;

	I915_WRITE(DP_A, dpa_ctl);

	POSTING_READ(DP_A);
@@ -1893,13 +1905,6 @@ intel_dp_link_down(struct intel_dp *intel_dp) 


	DRM_DEBUG_KMS("\n");



	if (is_edp(intel_dp)) {

		DP &= ~DP_PLL_ENABLE;

		I915_WRITE(intel_dp->output_reg, DP);

		POSTING_READ(intel_dp->output_reg);

		udelay(100);

	}



	if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {

		DP &= ~DP_LINK_TRAIN_MASK_CPT;

		I915_WRITE(intel_dp->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE_CPT);
@@ -2443,6 +2448,8 @@ intel_dp_init(struct drm_device *dev, int output_reg, enum port port) 


	intel_dp->output_reg = output_reg;

	intel_dp->port = port;

	/* Preserve the current hw state. */

	intel_dp->DP = I915_READ(intel_dp->output_reg);



	intel_connector = kzalloc(sizeof(struct intel_connector), GFP_KERNEL);

	if (!intel_connector) {