[BXT DSI timing fixes v1 3/3] drm/i915/bxt: Fixed dsi enc disable and blank at bootup

[Uma Shankar <uma.shankar@intel.com>]

During bootup, mipi display was blanking in BXT. This is because during
driver load, though encoder, connector were active but crtc returned
inactive. This caused sanitize function to disable the DSI panel. In AOS,
this is fine since HWC will do a modeset and crtc, connector, encoder
mapping will be restored. But in Charging OS, no modeset is called, it
just calls DPMS ON/OFF. Hence display doesn't come in COS. This is needed
even for seamless booting to Android without a blank.

This is fine on BYT/CHT since transcoder is common b/w all encoders. But
for BXT, there is a separate mipi transcoder. Hence this needs special
handling for BXT DSI.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |    3 +++
 drivers/gpu/drm/i915/intel_display.c |   27 +++++++++++++++++++++++----
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index bf14096..ae790ec 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1948,6 +1948,9 @@ struct drm_i915_private {
 	/* perform PHY state sanity checks? */
 	bool chv_phy_assert[2];
 
+	/* To check if DSI is initializing at bootup */
+	bool dsi_enumerating;
+
 	/*
 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
 	 * will be rejected. Instead look for a better place.
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 2717823..fe4f4f3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7711,6 +7711,9 @@ static void intel_get_pipe_timings(struct intel_crtc *crtc,
 	bool is_dsi = intel_pipe_has_type(crtc, INTEL_OUTPUT_DSI);
 	uint32_t tmp;
 
+	if (dev_priv->dsi_enumerating && dev_priv->vbt.has_mipi)
+		is_dsi = true;
+
 	tmp = I915_READ(HTOTAL(cpu_transcoder));
 	pipe_config->base.adjusted_mode.crtc_hdisplay = (tmp & 0xffff) + 1;
 	pipe_config->base.adjusted_mode.crtc_htotal = ((tmp >> 16) & 0xffff) + 1;
@@ -9825,10 +9828,20 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
 	is_dsi = intel_pipe_has_type(crtc, INTEL_OUTPUT_DSI);
 
 	/*
-	 * Check if encoder is enabled or not
+	 * Check if encoder is enabled or not.
 	 * Separate implementation for DSI and DDI encoders.
+	 * For first time during driver init, encoder association
+	 * would not have happened and this function will return
+	 * false. This will cause encoder to be disabled causing
+	 * a blank, till user space does a modeset. In order to avoid
+	 * this, if DSI is enabled in VBT, for first iteration, this
+	 * will return true since BIOS would have initialized MIPI.
+	 * This is needed for seamless booting without blanking and
+	 * for Charging OS scenario. Since DSI is the first display in
+	 * setup_outputs, hence first crtc will be associated with mipi
+	 * display
 	 */
-	if (is_dsi) {
+	if (is_dsi || (dev_priv->dsi_enumerating && dev_priv->vbt.has_mipi)) {
 		struct intel_encoder *encoder;
 
 		for_each_encoder_on_crtc(dev, &crtc->base, encoder) {
@@ -9852,8 +9865,11 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
 			if (dsi_enc_enabled)
 				break;
 		}
-		if (!dsi_enc_enabled)
-			return false;
+
+		 if (!dsi_enc_enabled) {
+			if (!dev_priv->dsi_enumerating)
+				return false;
+		}
 	} else {
 
 		tmp = I915_READ(TRANS_DDI_FUNC_CTL(TRANSCODER_EDP));
@@ -9921,6 +9937,8 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
 		pipe_config->pixel_multiplier = 1;
 	}
 
+	dev_priv->dsi_enumerating = false;
+
 	return true;
 }
 
@@ -14877,6 +14895,7 @@ void intel_modeset_init(struct drm_device *dev)
 	enum pipe pipe;
 	struct intel_crtc *crtc;
 
+	dev_priv->dsi_enumerating = true;
 	drm_mode_config_init(dev);
 
 	dev->mode_config.min_width = 0;
-- 
1.7.9.5

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