drm/vmwgfx: Unpin the screen object backup buffer when not used

We were relying on the pinned screen object backup buffer to be destroyed
when not used. But if we hold a copy of the atomic state, like when
hibernating, the backup buffer might not be destroyed since it's
refcounted by the atomic state. This causes us to hibernate with a
buffer pinned in VRAM.

Fix this by only having the buffer pinned when it is actually used by a
screen object.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>

1 files changed, 21 insertions, 8 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
index 3b7bf7ca18b9..419185f60278 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -405,7 +405,11 @@ vmw_sou_primary_plane_cleanup_fb(struct drm_plane *plane,
                                  struct drm_plane_state *old_state)
 {
         struct vmw_plane_state *vps = vmw_plane_state_to_vps(old_state);
+        struct drm_crtc *crtc = plane->state->crtc ?
+                plane->state->crtc : old_state->crtc;
 
+        if (vps->dmabuf)
+                vmw_dmabuf_unpin(vmw_priv(crtc->dev), vps->dmabuf, false);
         vmw_dmabuf_unreference(&vps->dmabuf);
         vps->dmabuf_size = 0;
 
@@ -443,10 +447,17 @@ vmw_sou_primary_plane_prepare_fb(struct drm_plane *plane,
         }
 
         size = new_state->crtc_w * new_state->crtc_h * 4;
+        dev_priv = vmw_priv(crtc->dev);
 
         if (vps->dmabuf) {
-                if (vps->dmabuf_size == size)
-                        return 0;
+                if (vps->dmabuf_size == size) {
+                        /*
+                         * Note that this might temporarily up the pin-count
+                         * to 2, until cleanup_fb() is called.
+                         */
+                        return vmw_dmabuf_pin_in_vram(dev_priv, vps->dmabuf,
+                                                      true);
+                }
 
                 vmw_dmabuf_unreference(&vps->dmabuf);
                 vps->dmabuf_size = 0;
@@ -456,7 +467,6 @@ vmw_sou_primary_plane_prepare_fb(struct drm_plane *plane,
         if (!vps->dmabuf)
                 return -ENOMEM;
 
-        dev_priv = vmw_priv(crtc->dev);
         vmw_svga_enable(dev_priv);
 
         /* After we have alloced the backing store might not be able to
@@ -467,13 +477,16 @@ vmw_sou_primary_plane_prepare_fb(struct drm_plane *plane,
                               &vmw_vram_ne_placement,
                               false, &vmw_dmabuf_bo_free);
         vmw_overlay_resume_all(dev_priv);
-
-        if (ret != 0)
+        if (ret) {
                 vps->dmabuf = NULL; /* vmw_dmabuf_init frees on error */
-        else
-                vps->dmabuf_size = size;
+                return ret;
+        }
 
-        return ret;
+        /*
+         * TTM already thinks the buffer is pinned, but make sure the
+         * pin_count is upped.
+         */
+        return vmw_dmabuf_pin_in_vram(dev_priv, vps->dmabuf, true);
 }