Simpledrm is "DMA" access is not limited. All CPU addressible memory can be used via direct DMA mappings.
Fixes following warning on Apple silicon systems. Physical memory on those systems starts at (1 << 35) or (1 << 40) so 32-bit direct DMA mappings are not possible.
------------[ cut here ]------------
simple-framebuffer 9e5064000.framebuffer: swiotlb addr 0x00000009de654000+16384 overflow (mask ffffffff, bus limit 0). WARNING: CPU: 3 PID: 961 at kernel/dma/swiotlb.c:928 swiotlb_map+0x1f4/0x2a0 Modules linked in: ...
CPU: 3 PID: 961 Comm: kwin_wayland Not tainted 6.5.0-asahi+ #1 Hardware name: Apple Mac mini (M2, 2023) (DT)
...
Call trace:
swiotlb_map+0x1f4/0x2a0
dma_direct_map_sg+0x8c/0x2a8
dma_map_sgtable+0x5c/0xd0
drm_gem_map_dma_buf+0x64/0xb8
dma_buf_map_attachment+0xac/0x158
dma_buf_map_attachment_unlocked+0x48/0x80
drm_gem_prime_import_dev+0xa0/0x1a0
drm_gem_prime_fd_to_handle+0xc8/0x218
drm_prime_fd_to_handle_ioctl+0x34/0x50
drm_ioctl_kernel+0xe4/0x160
drm_ioctl+0x23c/0x3e0
...
---[ end trace 0000000000000000 ]---
Avoids using swiotbl bounce buffers on other platforms when the mapped memory is above 4GB.
Simpledrm is "DMA" access is not limited. All CPU addressible memory can be used via direct DMA mappings.
Fixes following warning on Apple silicon systems. Physical memory on those systems starts at (1 << 35) or (1 << 40) so 32-bit direct DMA mappings are not possible. ------------[ cut here ]------------ simple-framebuffer 9e5064000.framebuffer: swiotlb addr 0x00000009de654000+16384 overflow (mask ffffffff, bus limit 0). WARNING: CPU: 3 PID: 961 at kernel/dma/swiotlb.c:928 swiotlb_map+0x1f4/0x2a0 Modules linked in: ... CPU: 3 PID: 961 Comm: kwin_wayland Not tainted 6.5.0-asahi+ #1 Hardware name: Apple Mac mini (M2, 2023) (DT) ... Call trace: swiotlb_map+0x1f4/0x2a0 dma_direct_map_sg+0x8c/0x2a8 dma_map_sgtable+0x5c/0xd0 drm_gem_map_dma_buf+0x64/0xb8 dma_buf_map_attachment+0xac/0x158 dma_buf_map_attachment_unlocked+0x48/0x80 drm_gem_prime_import_dev+0xa0/0x1a0 drm_gem_prime_fd_to_handle+0xc8/0x218 drm_prime_fd_to_handle_ioctl+0x34/0x50 drm_ioctl_kernel+0xe4/0x160 drm_ioctl+0x23c/0x3e0 ... ---[ end trace 0000000000000000 ]---
Avoids using swiotbl bounce buffers on other platforms when the mapped memory is above 4GB.
Fixes: 11e8f5fd223b ("drm: Add simpledrm driver")