Just try to set a 64-bit DMA mask first and retry with the smaller dma_mask
if dma_set_mask failed.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 
        bits = nvxx_mmu(&drm->device)->dma_bits;
        if (nvxx_device(&drm->device)->func->pci) {
-               if (drm->agp.bridge ||
-                    !dma_supported(dev->dev, DMA_BIT_MASK(bits)))
+               if (drm->agp.bridge)
                        bits = 32;
        } else if (device->func->tegra) {
                struct nvkm_device_tegra *tegra = device->func->tegra(device);
        }
 
        ret = dma_set_mask(dev->dev, DMA_BIT_MASK(bits));
+       if (ret && bits != 32) {
+               bits = 32;
+               ret = dma_set_mask(dev->dev, DMA_BIT_MASK(bits));
+       }
        if (ret)
                return ret;