Am 16.01.24 um 14:02 schrieb Yangyu Chen:
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 <cyy@xxxxxxxxxxxx>
---
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);
Please add __GFP_NOWARN here to avoid the backtrace and warning on
allocation failure.
if (unlikely(glob->dummy_read_page == NULL)) {
- ret = -ENOMEM;
- goto out;
+ /* Retry without GFP_DMA32 */
Well that is obvious, you need to describe why you retry without GFP_DMA32.
Something like /* Retry without GFP_DMA32 for platforms without
ZONE_DMA32 */, and probably better placed above the "if".
+ 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");
Well maybe make that a bit shorter, something like "Using GFP_DMA32
fallback for the dummy page".
Regards,
Christian.
}
INIT_LIST_HEAD(&glob->device_list);
