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Diffstat (limited to 'Documentation/DMA-mapping.txt')
| -rw-r--r-- | Documentation/DMA-mapping.txt | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/DMA-mapping.txt b/Documentation/DMA-mapping.txt index 684557474c15..ee4bb73683cd 100644 --- a/Documentation/DMA-mapping.txt +++ b/Documentation/DMA-mapping.txt @@ -199,6 +199,8 @@ address during PCI bus mastering you might do something like: "mydev: 24-bit DMA addressing not available.\n"); goto ignore_this_device; } +[Better use DMA_24BIT_MASK instead of 0x00ffffff. +See linux/include/dma-mapping.h for reference.] When pci_set_dma_mask() is successful, and returns zero, the PCI layer saves away this mask you have provided. The PCI layer will use this |