drm/vc4: Don't try to initialize FBDEV if we're only bound to V3D.

There's no sense in having an fbdev if there's no display, since
connectors don't get hotplugged to this hardware.  On Cygnus we were
getting a dmesg error from passing in num_connectors (0), when that
argument is supposed to be the maximum number of cloned connectors per
CRTC (1).

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170428224223.21904-2-eric@anholt.net

diff --git a/drivers/gpu/drm/vc4/vc4_kms.c b/drivers/gpu/drm/vc4/vc4_kms.c
index ad7925a9e0ea4c331bdad8474388e8e6058af1c8..237a504f11f0da3dc71301564a4bac752b64db98 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -230,10 +230,12 @@ int vc4_kms_load(struct drm_device *dev)
 
        drm_mode_config_reset(dev);
 
-       vc4->fbdev = drm_fbdev_cma_init(dev, 32,
-                                       dev->mode_config.num_connector);
-       if (IS_ERR(vc4->fbdev))
-               vc4->fbdev = NULL;
+       if (dev->mode_config.num_connector) {
+               vc4->fbdev = drm_fbdev_cma_init(dev, 32,
+                                               dev->mode_config.num_connector);
+               if (IS_ERR(vc4->fbdev))
+                       vc4->fbdev = NULL;
+       }
 
        drm_kms_helper_poll_init(dev);