Both brw_bo_map_cpu() & brw_bo_map_wc() assert if mapping the
underlying BO fails. Failing back to brw_bo_map_gtt() doesn't seem to
make any sense for that reason.
We also only call brw_bo_map_gtt() for tiled buffers which as far as
we know are never mapped coherent (coherent is a parameter reserved
for buffer object which are always allocated linear). So explicitly
assert if we ever run into this case.
This makes checking the kernel about whether GTT maps are actually
coherent unnecessary.
Signed-off-by: Lionel Landwerlin <lionel.g.landwer...@intel.com>
---
src/mesa/drivers/dri/i965/brw_bufmgr.c | 21 ++-------------------
1 file changed, 2 insertions(+), 19 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c
b/src/mesa/drivers/dri/i965/brw_bufmgr.c
index f1675b191c1..e0008905164 100644
--- a/src/mesa/drivers/dri/i965/brw_bufmgr.c
+++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c
@@ -1095,6 +1095,8 @@ brw_bo_map_gtt(struct brw_context *brw, struct brw_bo
*bo, unsigned flags)
{
struct brw_bufmgr *bufmgr = bo->bufmgr;
+ assert((flags & MAP_COHERENT) == 0);
+
/* Get a mapping of the buffer if we haven't before. */
if (bo->map_gtt == NULL) {
DBG("bo_map_gtt: mmap %d (%s)\n", bo->gem_handle, bo->name);
@@ -1186,25 +1188,6 @@ brw_bo_map(struct brw_context *brw, struct brw_bo *bo,
unsigned flags)
else
map = brw_bo_map_wc(brw, bo, flags);
- /* Allow the attempt to fail by falling back to the GTT where necessary.
- *
- * Not every buffer can be mmaped directly using the CPU (or WC), for
- * example buffers that wrap stolen memory or are imported from other
- * devices. For those, we have little choice but to use a GTT mmapping.
- * However, if we use a slow GTT mmapping for reads where we expected fast
- * access, that order of magnitude difference in throughput will be clearly
- * expressed by angry users.
- *
- * We skip MAP_RAW because we want to avoid map_gtt's fence detiling.
- */
- if (!map && !(flags & MAP_RAW)) {
- if (brw) {
- perf_debug("Fallback GTT mapping for %s with access flags %x\n",
- bo->name, flags);
- }
- map = brw_bo_map_gtt(brw, bo, flags);
- }
-
return map;
}
--
2.19.0.rc1
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