[PATCH 4.16 141/272] drm/vmwgfx: Unpin the screen object backup buffer when not used

Greg Kroah-Hartman
2018-05-28T11:48:40Z

From: Thomas Hellstrom <thellstrom@vmware.com>

[ Upstream commit 20fb5a635a0c8478ac98f15cfafc2ea83df29565 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c
@@ -453,7 +453,11 @@ vmw_sou_primary_plane_cleanup_fb(struct
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;

@@ -491,10 +495,17 @@ vmw_sou_primary_plane_prepare_fb(struct
}

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;
@@ -504,7 +515,6 @@ vmw_sou_primary_plane_prepare_fb(struct
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
@@ -515,13 +525,16 @@ vmw_sou_primary_plane_prepare_fb(struct
&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);
}