drm/crtc: take references to connectors used in a modeset. (v2)

This just takes a reference on the connector when we set a mode
in the non-atomic paths.

v2: Follow Daniel Stone's suggestions on when to take/drop
references.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 66ca313..f47a252 100644 (file)
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -456,6 +456,9 @@ drm_crtc_helper_disable(struct drm_crtc *crtc)
                         * between them is henceforth no longer available.
                         */
                        connector->dpms = DRM_MODE_DPMS_OFF;
+
+                       /* we keep a reference while the encoder is bound */
+                       drm_connector_unreference(connector);
                }
        }
 
@@ -606,6 +609,11 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                mode_changed = true;
        }
 
+       /* take a reference on all connectors in set */
+       for (ro = 0; ro < set->num_connectors; ro++) {
+               drm_connector_reference(set->connectors[ro]);
+       }
+
        /* a) traverse passed in connector list and get encoders for them */
        count = 0;
        drm_for_each_connector(connector, dev) {
@@ -724,6 +732,12 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
                }
        }
 
+       /* after fail drop reference on all connectors in save set */
+       count = 0;
+       drm_for_each_connector(connector, dev) {
+               drm_connector_unreference(&save_connectors[count++]);
+       }
+
        kfree(save_connectors);
        kfree(save_encoders);
        return 0;
@@ -740,6 +754,11 @@ fail:
                *connector = save_connectors[count++];
        }
 
+       /* after fail drop reference on all connectors in set */
+       for (ro = 0; ro < set->num_connectors; ro++) {
+               drm_connector_unreference(set->connectors[ro]);
+       }
+
        /* Try to restore the config */
        if (mode_changed &&
            !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,