From 0767935e8682157dc98bee03f821faa08b944fe8 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 6 Sep 2012 22:15:42 +0200 Subject: [PATCH] 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: Paulo Zanoni Signed-Off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dp.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index fccc82970ae0..0f8480037cf0 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -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) { -- 2.20.1