linux-kernel - [PATCH v3] drm/i915: Re-init lspcon after HPD if lspcon probe failed

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Message-Id: <20191224084251.28414-1-kai.heng.feng@canonical.com>
Date:   Tue, 24 Dec 2019 16:42:51 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     jani.nikula@...ux.intel.com, joonas.lahtinen@...ux.intel.com,
        rodrigo.vivi@...el.com, airlied@...ux.ie, daniel@...ll.ch
Cc:     ville.syrjala@...ux.intel.com, swati2.sharma@...el.com,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Kai-Heng Feng <kai.heng.feng@...onical.com>
Subject: [PATCH v3] drm/i915: Re-init lspcon after HPD if lspcon probe failed

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 in question only gets powered
after the cable is plugged.

So let's call lspcon_init() dynamically to properly initialize the
lspcon chip and make HDMI port work.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/203
Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
---
v3:
 - Make sure it's handled under long HPD case.

v2: 
 - Move lspcon_init() inside of intel_dp_hpd_pulse().

 drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index fe31bbfd6c62..a72c9c041c60 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -6573,6 +6573,7 @@ enum irqreturn
 intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 {
 	struct intel_dp *intel_dp = &intel_dig_port->dp;
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
 
 	if (long_hpd && intel_dig_port->base.type == INTEL_OUTPUT_EDP) {
 		/*
@@ -6593,7 +6594,12 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 		      long_hpd ? "long" : "short");
 
 	if (long_hpd) {
-		intel_dp->reset_link_params = true;
+		if (intel_dig_port->base.type == INTEL_OUTPUT_DDI &&
+		    HAS_LSPCON(dev_priv) && !intel_dig_port->lspcon.active)
+			lspcon_init(intel_dig_port);
+		else
+			intel_dp->reset_link_params = true;
+
 		return IRQ_NONE;
 	}
 
-- 
2.17.1