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

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Date:   Mon, 23 Dec 2019 17:56:04 +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] 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>
---
 drivers/gpu/drm/i915/display/intel_hotplug.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_hotplug.c b/drivers/gpu/drm/i915/display/intel_hotplug.c
index fc29046d48ea..e2862e36d0bf 100644
--- a/drivers/gpu/drm/i915/display/intel_hotplug.c
+++ b/drivers/gpu/drm/i915/display/intel_hotplug.c
@@ -28,6 +28,7 @@
 #include "i915_drv.h"
 #include "intel_display_types.h"
 #include "intel_hotplug.h"
+#include "intel_lspcon.h"
 
 /**
  * DOC: Hotplug
@@ -336,6 +337,8 @@ static void i915_digport_work_func(struct work_struct *work)
 			continue;
 
 		dig_port = enc_to_dig_port(&encoder->base);
+		if (HAS_LSPCON(dev_priv) && !dig_port->lspcon.active)
+			lspcon_init(dig_port);
 
 		ret = dig_port->hpd_pulse(dig_port, long_hpd);
 		if (ret == IRQ_NONE) {
-- 
2.17.1