drm/i915: Protect against deferred fbdev setup

We could probably hit this already with our current async fbdev init,
but it's much easier to hit this with the new deferred fbdev setup
that I'm working on polishing.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170706130023.28417-2-daniel.vetter@ffwll.ch

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 620c9218d1c10a35aca60a0ffe5de753d25790e1..2ef75c1a611957c6188402be8422a6e3c1ca4489 100644 (file)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1935,7 +1935,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
                return ret;
 
 #ifdef CONFIG_DRM_FBDEV_EMULATION
-       if (dev_priv->fbdev) {
+       if (dev_priv->fbdev && dev_priv->fbdev->helper.fb) {
                fbdev_fb = to_intel_framebuffer(dev_priv->fbdev->helper.fb);
 
                seq_printf(m, "fbcon size: %d x %d, depth %d, %d bpp, modifier 0x%llx, refcount %d, obj ",