drm/nouveau/sw: fix oops if gpu has its display block disabled

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/core/engine/software/nv50.c b/drivers/gpu/drm/nouveau/core/engine/software/nv50.c
index b574dd4..5ce686e 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/engine/software/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/engine/software/nv50.c
@@ -176,7 +176,7 @@ nv50_software_context_ctor(struct nouveau_object *parent,
        if (ret)
                return ret;
 
-       chan->vblank.nr_event = pdisp->vblank->index_nr;
+       chan->vblank.nr_event = pdisp ? pdisp->vblank->index_nr : 0;
        chan->vblank.event = kzalloc(chan->vblank.nr_event *
                                     sizeof(*chan->vblank.event), GFP_KERNEL);
        if (!chan->vblank.event)