[PATCH 3/3] drm/ttm: Fix memory space allocation v2

[Thomas Hellstrom]

In the event that TTM doesn't find a compatible memory type for the
driver's first placement choice (placement without eviction), TTM
returns -EINVAL without trying the driver's second choice.
This causes problems on vmwgfx when VRAM is disabled before first modeset
and during VT switches when fbdev is not enabled.

Fix this by also trying the driver's second choice before returning
-EINVAL.

v2: Also check that man->use_type is true for the driver's second choice.
Fixes a bug where disallowed memory types could be used.

Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
Reviewed-by: Sinclair Yeh <syeh at vmware.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 8d9b7de..745e996 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -882,6 +882,8 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (ret)
 			return ret;
 		man = &bdev->man[mem_type];
+		if (!man->has_type || !man->use_type)
+			continue;
 
 		type_ok = ttm_bo_mt_compatible(man, mem_type, place,
 						&cur_flags);
@@ -889,6 +891,7 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (!type_ok)
 			continue;
 
+		type_found = true;
 		cur_flags = ttm_bo_select_caching(man, bo->mem.placement,
 						  cur_flags);
 		/*
@@ -901,12 +904,10 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (mem_type == TTM_PL_SYSTEM)
 			break;
 
-		if (man->has_type && man->use_type) {
-			type_found = true;
-			ret = (*man->func->get_node)(man, bo, place, mem);
-			if (unlikely(ret))
-				return ret;
-		}
+		ret = (*man->func->get_node)(man, bo, place, mem);
+		if (unlikely(ret))
+			return ret;
+		
 		if (mem->mm_node)
 			break;
 	}
@@ -917,9 +918,6 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		return 0;
 	}
 
-	if (!type_found)
-		return -EINVAL;
-
 	for (i = 0; i < placement->num_busy_placement; ++i) {
 		const struct ttm_place *place = &placement->busy_placement[i];
 
@@ -927,11 +925,12 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (ret)
 			return ret;
 		man = &bdev->man[mem_type];
-		if (!man->has_type)
+		if (!man->has_type || !man->use_type)
 			continue;
 		if (!ttm_bo_mt_compatible(man, mem_type, place, &cur_flags))
 			continue;
 
+		type_found = true;
 		cur_flags = ttm_bo_select_caching(man, bo->mem.placement,
 						  cur_flags);
 		/*
@@ -957,8 +956,13 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 		if (ret == -ERESTARTSYS)
 			has_erestartsys = true;
 	}
-	ret = (has_erestartsys) ? -ERESTARTSYS : -ENOMEM;
-	return ret;
+
+	if (!type_found) {
+		printk(KERN_ERR TTM_PFX "No compatible memory type found.\n");
+		return -EINVAL;
+	}
+
+	return (has_erestartsys) ? -ERESTARTSYS : -ENOMEM;
 }
 EXPORT_SYMBOL(ttm_bo_mem_space);
 
-- 
2.1.0