Some platforms may not have any memory in ZONE_DMA32 and use IOMMU to allow
32-bit-DMA-only device to work. Forcing GFP_DMA32 on dummy_read_page will
fail on such platforms. Retry after fail will get this works on such
platforms.

Signed-off-by: Yangyu Chen <c...@cyyself.name>
---
 drivers/gpu/drm/ttm/ttm_device.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index d48b39132b32..a07d9ea919b6 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -98,8 +98,13 @@ static int ttm_global_init(void)
        glob->dummy_read_page = alloc_page(__GFP_ZERO | GFP_DMA32);
 
        if (unlikely(glob->dummy_read_page == NULL)) {
-               ret = -ENOMEM;
-               goto out;
+               /* Retry without GFP_DMA32 */
+               glob->dummy_read_page = alloc_page(__GFP_ZERO);
+               if (unlikely(glob->dummy_read_page == NULL)) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               pr_warn("Failed to allocate dummy_read_page with GFP_DMA32, 
some old graphics card only has 32bit DMA may not work properly.\n");
        }
 
        INIT_LIST_HEAD(&glob->device_list);
-- 
2.43.0

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