drm/gma500: move fbcon restore to lastclose

Doing this within the fb->destroy callback leads to a locking
nightmare. And all other drm drivers that restore the fbcon do
it in lastclose, too.

With this adjustments all fb->destroy callbacks optionally drop
references to any gem objects used as backing storage, call
drm_framebuffer_cleanup and then kfree the struct. Which nicely
simplifies the locking for framebuffer unreferencing and freeing,
since this doesn't require that we hold the mode_config lock. A
slight exception is the vmwgfx surface backed framebuffer, it also
calls drm_master_put and removes the object from a device-private
framebuffer list. Both seem to have solid locking in place already.

Conclusion is that now it is no longer required to hold the
mode_config lock while freeing a framebuffer.

v2: Drop the corresponding mutex_lock WARN check from
drm_framebuffer_unreference.

v3: Use just the mode_config lock not modeset_lock_all, due to patch
reordering.

Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

3 files changed, 10 insertions, 26 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 81545540b2df..8d665fafc15e 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -317,9 +317,7 @@ static void drm_framebuffer_free(struct kref *kref)
  */
 void drm_framebuffer_unreference(struct drm_framebuffer *fb)
 {
-        struct drm_device *dev = fb->dev;
         DRM_DEBUG("FB ID: %d\n", fb->base.id);
-        WARN_ON(!drm_modeset_is_locked(dev));
         kref_put(&fb->refcount, drm_framebuffer_free);
 }
 EXPORT_SYMBOL(drm_framebuffer_unreference);
diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 38e7e7597de2..49800d2b79dd 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -668,30 +668,6 @@ static void psb_user_framebuffer_destroy(struct drm_framebuffer *fb)
 {
         struct psb_framebuffer *psbfb = to_psb_fb(fb);
         struct gtt_range *r = psbfb->gtt;
-        struct drm_device *dev = fb->dev;
-        struct drm_psb_private *dev_priv = dev->dev_private;
-        struct psb_fbdev *fbdev = dev_priv->fbdev;
-        struct drm_crtc *crtc;
-        int reset = 0;
-
-        /* Should never get stolen memory for a user fb */
-        WARN_ON(r->stolen);
-
-        /* Check if we are erroneously live */
-        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
-                if (crtc->fb == fb)
-                        reset = 1;
-
-        if (reset)
-                /*
-                 * Now force a sane response before we permit the DRM CRTC
-                 * layer to do stupid things like blank the display. Instead
-                 * we reset this framebuffer as if the user had forced a reset.
-                 * We must do this before the cleanup so that the DRM layer
-                 * doesn't get a chance to stick its oar in where it isn't
-                 * wanted.
-                 */
-                drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper);
 
         /* Let DRM do its clean up */
         drm_framebuffer_cleanup(fb);
diff --git a/drivers/gpu/drm/gma500/psb_drv.c b/drivers/gpu/drm/gma500/psb_drv.c
index dd1fbfa7e467..dbcefe9f78fa 100644
--- a/drivers/gpu/drm/gma500/psb_drv.c
+++ b/drivers/gpu/drm/gma500/psb_drv.c
@@ -149,6 +149,16 @@ static struct drm_ioctl_desc psb_ioctls[] = {
 
 static void psb_lastclose(struct drm_device *dev)
 {
+        int ret;
+        struct drm_psb_private *dev_priv = dev->dev_private;
+        struct psb_fbdev *fbdev = dev_priv->fbdev;
+
+        mutex_lock(&dev->mode_config.mutex);
+        ret = drm_fb_helper_restore_fbdev_mode(&fbdev->psb_fb_helper);
+        if (ret)
+                DRM_DEBUG("failed to restore crtc mode\n");
+        mutex_unlock(&dev->mode_config.mutex);
+
         return;
 }