drm/i915: Init lspcon after HPD in intel_dp_detect()

On HP 800 G4 DM, if HDMI cable isn't plugged before boot, the HDMI port
becomes useless and never responds to cable hotplugging:
[    3.031904] [drm:lspcon_init [i915]] *ERROR* Failed to probe lspcon
[    3.031945] [drm:intel_ddi_init [i915]] *ERROR* LSPCON init failed on port D

Seems like the lspcon chip on the system only gets powered after the
cable is plugged.

Consilidate lspcon_init() into lspcon_resume() to dynamically init
lspcon chip, and make HDMI port work.

v6:
 - Rebase on latest for-linux-next.
v5:
 - Consolidate lspcon_resume() with lspcon_init().
 - Move more logic into lspcon code.
v4:
 - Trust VBT in intel_infoframe_init().
 - Init lspcon in intel_dp_detect().
v3:
 - Make sure it's handled under long HPD case.
v2:
 - Move lspcon_init() inside of intel_dp_hpd_pulse().

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/203
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200610075542.12882-1-kai.heng.feng@canonical.com

1 files changed, 34 insertions, 27 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_lspcon.c b/drivers/gpu/drm/i915/display/intel_lspcon.c
index dc1b35559afd..db2e1e938572 100644
--- a/drivers/gpu/drm/i915/display/intel_lspcon.c
+++ b/drivers/gpu/drm/i915/display/intel_lspcon.c
@@ -525,26 +525,6 @@ u32 lspcon_infoframes_enabled(struct intel_encoder *encoder,
 	return 0;
 }
 
-void lspcon_resume(struct intel_lspcon *lspcon)
-{
-	enum drm_lspcon_mode expected_mode;
-
-	if (lspcon_wake_native_aux_ch(lspcon)) {
-		expected_mode = DRM_LSPCON_MODE_PCON;
-		lspcon_resume_in_pcon_wa(lspcon);
-	} else {
-		expected_mode = DRM_LSPCON_MODE_LS;
-	}
-
-	if (lspcon_wait_mode(lspcon, expected_mode) == DRM_LSPCON_MODE_PCON)
-		return;
-
-	if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON))
-		DRM_ERROR("LSPCON resume failed\n");
-	else
-		DRM_DEBUG_KMS("LSPCON resume success\n");
-}
-
 void lspcon_wait_pcon_mode(struct intel_lspcon *lspcon)
 {
 	lspcon_wait_mode(lspcon, DRM_LSPCON_MODE_PCON);
@@ -554,15 +534,8 @@ bool lspcon_init(struct intel_digital_port *dig_port)
 {
 	struct intel_dp *dp = &dig_port->dp;
 	struct intel_lspcon *lspcon = &dig_port->lspcon;
-	struct drm_device *dev = dig_port->base.base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct drm_connector *connector = &dp->attached_connector->base;
 
-	if (!HAS_LSPCON(dev_priv)) {
-		DRM_ERROR("LSPCON is not supported on this platform\n");
-		return false;
-	}
-
 	lspcon->active = false;
 	lspcon->mode = DRM_LSPCON_MODE_INVALID;
 
@@ -586,3 +559,37 @@ bool lspcon_init(struct intel_digital_port *dig_port)
 	DRM_DEBUG_KMS("Success: LSPCON init\n");
 	return true;
 }
+
+void lspcon_resume(struct intel_digital_port *dig_port)
+{
+	struct intel_lspcon *lspcon = &dig_port->lspcon;
+	struct drm_device *dev = dig_port->base.base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	enum drm_lspcon_mode expected_mode;
+
+	if (!intel_bios_is_lspcon_present(dev_priv, dig_port->base.port))
+		return;
+
+	if (!lspcon->active) {
+		if (!lspcon_init(dig_port)) {
+			DRM_ERROR("LSPCON init failed on port %c\n",
+				  port_name(dig_port->base.port));
+			return;
+		}
+	}
+
+	if (lspcon_wake_native_aux_ch(lspcon)) {
+		expected_mode = DRM_LSPCON_MODE_PCON;
+		lspcon_resume_in_pcon_wa(lspcon);
+	} else {
+		expected_mode = DRM_LSPCON_MODE_LS;
+	}
+
+	if (lspcon_wait_mode(lspcon, expected_mode) == DRM_LSPCON_MODE_PCON)
+		return;
+
+	if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON))
+		DRM_ERROR("LSPCON resume failed\n");
+	else
+		DRM_DEBUG_KMS("LSPCON resume success\n");
+}