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drm/vmwgfx: Check pin count before attempting to move a buffer 

In certain scenarios, e.g. when fbdev is enabled, we can get into
a situation where a vmw_framebuffer_pin() is called on a buffer
that is already pinned.

When this happens, ttm_bo_validate() will unintentially remove the
TTM_PL_FLAG_NO_EVICT flag, thus unpinning it, and leaving no way
to actually pin the buffer again.

To prevent this, if a buffer is already pinned, then instead of
calling ttm_bo_validate(), just make sure the proposed placement is
compatible with the existing placement.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: <stable@vger.kernel.org>
---
This is the 2nd patch in a 3-patch series to fix a console black
screen issue on Ubuntu 16.04 server.  This fixes a BUG_ON()
condition where a pinned buffer gets accidentally put onto the
LRU list.
This commit is contained in:
Sinclair Yeh 2016-06-29 13:20:26 -07:00
parent 94477bff39
commit 4ed7e2242b
1 changed files with 22 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/gpu/drm/vmwgfx/vmwgfx_dmabuf.c
View File

@ -49,6 +49,7 @@ int vmw_dmabuf_pin_in_placement(struct vmw_private *dev_priv,
{
struct ttm_buffer_object *bo = &buf->base;
int ret;
uint32_t new_flags;
ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
if (unlikely(ret != 0))
@ -60,7 +61,12 @@ int vmw_dmabuf_pin_in_placement(struct vmw_private *dev_priv,
if (unlikely(ret != 0))
goto err;
ret = ttm_bo_validate(bo, placement, interruptible, false);
if (buf->pin_count > 0)
ret = ttm_bo_mem_compat(placement, &bo->mem,
&new_flags) == true ? 0 : -EINVAL;
else
ret = ttm_bo_validate(bo, placement, interruptible, false);
if (!ret)
vmw_bo_pin_reserved(buf, true);
@ -91,6 +97,7 @@ int vmw_dmabuf_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
{
struct ttm_buffer_object *bo = &buf->base;
int ret;
uint32_t new_flags;
ret = ttm_write_lock(&dev_priv->reservation_sem, interruptible);
if (unlikely(ret != 0))
@ -102,6 +109,12 @@ int vmw_dmabuf_pin_in_vram_or_gmr(struct vmw_private *dev_priv,
if (unlikely(ret != 0))
goto err;
if (buf->pin_count > 0) {
ret = ttm_bo_mem_compat(&vmw_vram_gmr_placement, &bo->mem,
&new_flags) == true ? 0 : -EINVAL;
goto out_unreserve;
}
ret = ttm_bo_validate(bo, &vmw_vram_gmr_placement, interruptible,
false);
if (likely(ret == 0) || ret == -ERESTARTSYS)
@ -161,6 +174,7 @@ int vmw_dmabuf_pin_in_start_of_vram(struct vmw_private *dev_priv,
struct ttm_placement placement;
struct ttm_place place;
int ret = 0;
uint32_t new_flags;
place = vmw_vram_placement.placement[0];
place.lpfn = bo->num_pages;
@ -185,10 +199,15 @@ int vmw_dmabuf_pin_in_start_of_vram(struct vmw_private *dev_priv,
*/
if (bo->mem.mem_type == TTM_PL_VRAM &&
bo->mem.start < bo->num_pages &&
bo->mem.start > 0)
bo->mem.start > 0 &&
buf->pin_count == 0)
(void) ttm_bo_validate(bo, &vmw_sys_placement, false, false);
ret = ttm_bo_validate(bo, &placement, interruptible, false);
if (buf->pin_count > 0)
ret = ttm_bo_mem_compat(&placement, &bo->mem,
&new_flags) == true ? 0 : -EINVAL;
else
ret = ttm_bo_validate(bo, &placement, interruptible, false);
/* For some reason we didn't end up at the start of vram */
WARN_ON(ret == 0 && bo->offset != 0);