drm/fb-helper: Fix fb refcounting in pan_display_atomic

In

commit bbb1e52402b2a288b09ae37e8182599931c7e9df
Author: Rob Clark <robdclark@gmail.com>
Date:   Tue Aug 25 15:35:58 2015 -0400

    drm/fb-helper: atomic restore_fbdev_mode()..

we've forgotten to do the plane->old_fb refcount dance for
pan_display_atomic, which can result in refcount leaks if the current
configuration is not from fbcon. Which apparently can happen when
vt-switching - fbcon does a pan first before a set_par.

OCD-align function parameters while at it.

v2: Actually git add the OCD.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92483
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445015490-27682-1-git-send-email-daniel.vetter@ffwll.ch
Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 80e06316b52020d320fb7cbeb25d7be0df77b2cb..5b2de1b3c0207fbab617f5961aa0ffc425a42c8b 100644 (file)
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1227,7 +1227,7 @@ int drm_fb_helper_set_par(struct fb_info *info)
 EXPORT_SYMBOL(drm_fb_helper_set_par);
 
 static int pan_display_atomic(struct fb_var_screeninfo *var,
-               struct fb_info *info)
+                             struct fb_info *info)
 {
        struct drm_fb_helper *fb_helper = info->par;
        struct drm_device *dev = fb_helper->dev;
@@ -1245,6 +1245,8 @@ retry:
 
                mode_set = &fb_helper->crtc_info[i].mode_set;
 
+               mode_set->crtc->primary->old_fb = mode_set->crtc->primary->fb;
+
                mode_set->x = var->xoffset;
                mode_set->y = var->yoffset;
 
@@ -1260,13 +1262,34 @@ retry:
        info->var.xoffset = var->xoffset;
        info->var.yoffset = var->yoffset;
 
-       return 0;
 
 fail:
+       for(i = 0; i < fb_helper->crtc_count; i++) {
+               struct drm_mode_set *mode_set;
+               struct drm_plane *plane;
+
+               mode_set = &fb_helper->crtc_info[i].mode_set;
+               plane = mode_set->crtc->primary;
+
+               if (ret == 0) {
+                       struct drm_framebuffer *new_fb = plane->state->fb;
+
+                       if (new_fb)
+                               drm_framebuffer_reference(new_fb);
+                       plane->fb = new_fb;
+                       plane->crtc = plane->state->crtc;
+
+                       if (plane->old_fb)
+                               drm_framebuffer_unreference(plane->old_fb);
+               }
+               plane->old_fb = NULL;
+       }
+
        if (ret == -EDEADLK)
                goto backoff;
 
-       drm_atomic_state_free(state);
+       if (ret != 0)
+               drm_atomic_state_free(state);
 
        return ret;