[Nouveau] [PATCH] Accept 3d controllers and not only VGA controllers.

[Josef Larsson]

Accept 3d controllers and not only VGA controllers. According to Ilia
Mirkin,
the VGA controller check should be removed. This makes it possible
to use external connectors on a docking station (40A5) for a Thinkpad P51.
(See Bug 101778).

lspci example:

01:00.0 3D controller: NVIDIA Corporation GM107GLM [Quadro M1200 Mobile]
(rev a2)

Also include safe-guards to avoid NULL dereferencing of fbcon, which is
how this bug was found.
---
 drivers/gpu/drm/nouveau/nouveau_fbcon.c |  3 +--
 drivers/gpu/drm/nouveau/nv50_display.c  | 13 +++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index 2b12d82aac15..6b4d374a9d82 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -498,8 +498,7 @@ nouveau_fbcon_init(struct drm_device *dev)
     int preferred_bpp;
     int ret;
 
-    if (!dev->mode_config.num_crtc ||
-        (dev->pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+    if (!dev->mode_config.num_crtc)
         return 0;
 
     fbcon = kzalloc(sizeof(struct nouveau_fbdev), GFP_KERNEL);
diff --git a/drivers/gpu/drm/nouveau/nv50_display.c
b/drivers/gpu/drm/nouveau/nv50_display.c
index fb47d46050ec..061daf036407 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -3214,6 +3214,13 @@ nv50_mstm_destroy_connector(struct
drm_dp_mst_topology_mgr *mgr,
     struct nouveau_drm *drm = nouveau_drm(connector->dev);
     struct nv50_mstc *mstc = nv50_mstc(connector);
 
+    if (!drm->fbcon)
+    {
+        NV_WARN(drm, "drm->fbcon of %s point to NULL. Will not destroy
connector\n",
+            connector->name);
+        return;
+    }
+
     drm_connector_unregister(&mstc->connector);
 
     drm_modeset_lock_all(drm->dev);
@@ -3229,6 +3236,12 @@ nv50_mstm_register_connector(struct drm_connector
*connector)
 {
     struct nouveau_drm *drm = nouveau_drm(connector->dev);
 
+    if (!drm->fbcon)
+    {
+        NV_WARN(drm, "drm->fbcon of %s point to NULL. Will not register
connector\n",
+            connector->name);
+        return;
+    }
     drm_modeset_lock_all(drm->dev);
     drm_fb_helper_add_one_connector(&drm->fbcon->helper, connector);
     drm_modeset_unlock_all(drm->dev);
-- 
2.13.6

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