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

[Kai-Heng Feng]

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 at canonical.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