diff options
Diffstat (limited to 'Documentation/usb/dma.txt')
-rw-r--r-- | Documentation/usb/dma.txt | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/usb/dma.txt b/Documentation/usb/dma.txt index 444651e70d9..84ef865237d 100644 --- a/Documentation/usb/dma.txt +++ b/Documentation/usb/dma.txt | |||
@@ -7,7 +7,7 @@ API OVERVIEW | |||
7 | 7 | ||
8 | The big picture is that USB drivers can continue to ignore most DMA issues, | 8 | The big picture is that USB drivers can continue to ignore most DMA issues, |
9 | though they still must provide DMA-ready buffers (see | 9 | though they still must provide DMA-ready buffers (see |
10 | Documentation/DMA-API-HOWTO.txt). That's how they've worked through | 10 | Documentation/PCI/PCI-DMA-mapping.txt). That's how they've worked through |
11 | the 2.4 (and earlier) kernels. | 11 | the 2.4 (and earlier) kernels. |
12 | 12 | ||
13 | OR: they can now be DMA-aware. | 13 | OR: they can now be DMA-aware. |
@@ -57,7 +57,7 @@ and effects like cache-trashing can impose subtle penalties. | |||
57 | force a consistent memory access ordering by using memory barriers. It's | 57 | force a consistent memory access ordering by using memory barriers. It's |
58 | not using a streaming DMA mapping, so it's good for small transfers on | 58 | not using a streaming DMA mapping, so it's good for small transfers on |
59 | systems where the I/O would otherwise thrash an IOMMU mapping. (See | 59 | systems where the I/O would otherwise thrash an IOMMU mapping. (See |
60 | Documentation/DMA-API-HOWTO.txt for definitions of "coherent" and | 60 | Documentation/PCI/PCI-DMA-mapping.txt for definitions of "coherent" and |
61 | "streaming" DMA mappings.) | 61 | "streaming" DMA mappings.) |
62 | 62 | ||
63 | Asking for 1/Nth of a page (as well as asking for N pages) is reasonably | 63 | Asking for 1/Nth of a page (as well as asking for N pages) is reasonably |
@@ -88,7 +88,7 @@ WORKING WITH EXISTING BUFFERS | |||
88 | Existing buffers aren't usable for DMA without first being mapped into the | 88 | Existing buffers aren't usable for DMA without first being mapped into the |
89 | DMA address space of the device. However, most buffers passed to your | 89 | DMA address space of the device. However, most buffers passed to your |
90 | driver can safely be used with such DMA mapping. (See the first section | 90 | driver can safely be used with such DMA mapping. (See the first section |
91 | of Documentation/DMA-API-HOWTO.txt, titled "What memory is DMA-able?") | 91 | of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?") |
92 | 92 | ||
93 | - When you're using scatterlists, you can map everything at once. On some | 93 | - When you're using scatterlists, you can map everything at once. On some |
94 | systems, this kicks in an IOMMU and turns the scatterlists into single | 94 | systems, this kicks in an IOMMU and turns the scatterlists into single |