From 0bc254257bfd9b25f64a68b719ee70a303b6d051 Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Sun, 17 Nov 2013 23:30:38 -0800 Subject: [PATCH] drm/ttm: Don't move non-existing data If ttm_bo_move_memcpy was instructed to move a non-populated ttm to io memory, it would first populate the ttm, then move the data and then destroy the ttm. That's stupid. However, some drivers might have relied on this to clear io memory from old stuff. So instead of a NOP, which would be the most efficient, just clear the destination. Signed-off-by: Thomas Hellstrom Reviewed-by: Jakob Bornecrantz --- drivers/gpu/drm/ttm/ttm_bo_util.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 4834c463c38b..15b86a94949d 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -350,10 +350,13 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo, goto out2; /* - * Move nonexistent data. NOP. + * Don't move nonexistent data. Clear destination instead. */ - if (old_iomap == NULL && ttm == NULL) + if (old_iomap == NULL && + (ttm == NULL || ttm->state == tt_unpopulated)) { + memset_io(new_iomap, 0, new_mem->num_pages*PAGE_SIZE); goto out2; + } /* * TTM might be null for moves within the same region. -- 2.20.1