[PATCH 4/5] drm/vmwgfx: Fix vmw_du_get_cursor_mob fencing of newly-created MOBs

[Zack Rusin]

From: Martin Krastev <martin.kras...@broadcom.com>

The fencing of MOB creation used in vmw_du_get_cursor_mob was incompatible
with register-based device communication employed by this routine. As a
result cursor MOB creation was racy, leading to potentially broken/missing
mouse cursor on desktops using CursorMob device feature.

Fixes: 53bc3f6fb6b3 ("drm/vmwgfx: Clean up cursor mobs")
Signed-off-by: Martin Krastev <martin.kras...@broadcom.com>
Reviewed-by: Maaz Mombasawala <maaz.mombasaw...@broadcom.com>
Reviewed-by: Zack Rusin <zack.ru...@broadcom.com>
Signed-off-by: Zack Rusin <zack.ru...@broadcom.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 2398041502c9..e2bfaf4522a6 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -273,6 +273,7 @@ static int vmw_du_get_cursor_mob(struct vmw_cursor_plane 
*vcp,
        u32 size = vmw_du_cursor_mob_size(vps->base.crtc_w, vps->base.crtc_h);
        u32 i;
        u32 cursor_max_dim, mob_max_size;
+       struct vmw_fence_obj *fence = NULL;
        int ret;
 
        if (!dev_priv->has_mob ||
@@ -314,7 +315,15 @@ static int vmw_du_get_cursor_mob(struct vmw_cursor_plane 
*vcp,
        if (ret != 0)
                goto teardown;
 
-       vmw_bo_fence_single(&vps->cursor.bo->tbo, NULL);
+       ret = vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
+       if (ret != 0) {
+               ttm_bo_unreserve(&vps->cursor.bo->tbo);
+               goto teardown;
+       }
+
+       dma_fence_wait(&fence->base, false);
+       dma_fence_put(&fence->base);
+
        ttm_bo_unreserve(&vps->cursor.bo->tbo);
        return 0;
 
-- 
2.40.1