Re: [Intel-gfx] 4.10-rc2 oops in DRM connector code

[Chris Wilson <chris@chris-wilson.co.uk>]

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On Wed, Jan 11, 2017 at 07:24:45AM -0800, Dave Hansen wrote:
> On 01/10/2017 11:43 PM, Daniel Vetter wrote:
> > On Tue, Jan 10, 2017 at 08:52:47AM -0800, Dave Hansen wrote:
> >> On 01/10/2017 02:31 AM, Daniel Vetter wrote:
> >>> commit e73ab00e9a0f1731f34d0620a9c55f5c30c4ad4e
> >>> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> >>> Date:   Sun Dec 18 14:35:45 2016 +0100
> >>>
> >>>     drm: prevent double-(un)registration for connectors
> >>>
> >>> Lack of that would perfectly explain that oops ... Otherwise still no idea
> >>> what's going wrong.
> >> No...  That's not in mainline as far as I can see.  Should I test with
> >> it applied?
> > Hm, I guess failed to cc: stable that one properly, iirc we decided the
> > race fix is too academic and can't be hit in reality ;-)
> > 
> > Testing would be great. Probably conflicts because we extracted
> > drm_connector.c only recently, but running s/drm_connector\.c/drm_crtc.c/
> > over the diff and then applying with some fudge should take care of that.
> 
> It doesn't apply to mainline, with or without the substitution you suggest.

I was hoping that the locking was the real cause here and would be an
easy fix to apply. I did have a look at trying to reorder the DP-MST
worker with driver registration. Hacky to say the least.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

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>From 30ac9092e934295f12775f03d73170fc480b7fc8 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 10 Jan 2017 10:46:25 +0000
Subject: [PATCH] dp-mst-register

---
 drivers/gpu/drm/i915/intel_dp.c     | 12 +++++++++++-
 drivers/gpu/drm/i915/intel_dp_mst.c |  9 ++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f0f44cdbe4b4..fc10eb2c8563 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4762,7 +4762,17 @@ intel_dp_connector_register(struct drm_connector *connector)
 		      intel_dp->aux.name, connector->kdev->kobj.name);
 
 	intel_dp->aux.dev = connector->kdev;
-	return drm_dp_aux_register(&intel_dp->aux);
+	ret = drm_dp_aux_register(&intel_dp->aux);
+	if (ret)
+		return ret;
+
+	if (intel_dp->mst_mgr.cbs) {
+		intel_dp->can_mst = true;
+		if (intel_dp->attached_connector)
+			intel_dp->attached_connector->base.status = intel_dp_long_pulse(intel_dp->attached_connector);
+	}
+
+	return 0;
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index c93c1999a494..f0a664041dbc 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -582,16 +582,19 @@ intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_ba
 	struct drm_device *dev = intel_dig_port->base.base.dev;
 	int ret;
 
-	intel_dp->can_mst = true;
+	intel_dp->can_mst = false;
 	intel_dp->mst_mgr.cbs = &mst_cbs;
 
 	/* create encoders */
 	intel_dp_create_fake_mst_encoders(intel_dig_port);
-	ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, dev->dev, &intel_dp->aux, 16, 3, conn_base_id);
+	ret = drm_dp_mst_topology_mgr_init(&intel_dp->mst_mgr, dev->dev,
+					    &intel_dp->aux, 16, 3,
+					    conn_base_id);
 	if (ret) {
-		intel_dp->can_mst = false;
+		intel_dp->mst_mgr.cbs = NULL;
 		return ret;
 	}
+
 	return 0;
 }
 
-- 
2.11.0