radeon: avoid possible divide by 0 in surface manager

Some users report hitting a divide by 0 with the tile split in
certain apps.  Tile_split shouldn't ever be 0 unless the surface
structure was not properly initialized.  I think there may be some
cases where mesa uses an improperly initialized surface struct,
but I haven't had time to track it down.

Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=72425

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

diff --git a/radeon/radeon_surface.c b/radeon/radeon_surface.c
index dcbbfdc..15127d4 100644 (file)
--- a/radeon/radeon_surface.c
+++ b/radeon/radeon_surface.c
@@ -655,7 +655,7 @@ static int eg_surface_init_2d(struct radeon_surface_manager *surf_man,
     tileb = tilew * tileh * bpe * surf->nsamples;
     /* slices per tile */
     slice_pt = 1;
-    if (tileb > tile_split) {
+    if (tileb > tile_split && tile_split) {
         slice_pt = tileb / tile_split;
     }
     tileb = tileb / slice_pt;
@@ -1621,7 +1621,7 @@ static int si_surface_init_2d(struct radeon_surface_manager *surf_man,
     tileb = tilew * tileh * bpe * surf->nsamples;
     /* slices per tile */
     slice_pt = 1;
-    if (tileb > tile_split) {
+    if (tileb > tile_split && tile_split) {
         slice_pt = tileb / tile_split;
     }
     tileb = tileb / slice_pt;
@@ -2223,7 +2223,7 @@ static int cik_surface_init_2d(struct radeon_surface_manager *surf_man,
 
     /* slices per tile */
     slice_pt = 1;
-    if (tileb > tile_split) {
+    if (tileb > tile_split && tile_split) {
         slice_pt = tileb / tile_split;
         tileb = tileb / slice_pt;
     }