diff options
Diffstat (limited to 'Documentation/debugging-via-ohci1394.txt')
-rw-r--r-- | Documentation/debugging-via-ohci1394.txt | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt index de4804e8b396..c360d4e91b48 100644 --- a/Documentation/debugging-via-ohci1394.txt +++ b/Documentation/debugging-via-ohci1394.txt | |||
@@ -36,14 +36,15 @@ available (notebooks) or too slow for extensive debug information (like ACPI). | |||
36 | Drivers | 36 | Drivers |
37 | ------- | 37 | ------- |
38 | 38 | ||
39 | The OHCI-1394 drivers in drivers/firewire and drivers/ieee1394 initialize | 39 | The ohci1394 driver in drivers/ieee1394 initializes the OHCI-1394 controllers |
40 | the OHCI-1394 controllers to a working state and can be used to enable | 40 | to a working state and enables physical DMA by default for all remote nodes. |
41 | physical DMA. By default you only have to load the driver, and physical | 41 | This can be turned off by ohci1394's module parameter phys_dma=0. |
42 | DMA access will be granted to all remote nodes, but it can be turned off | 42 | |
43 | when using the ohci1394 driver. | 43 | The alternative firewire-ohci driver in drivers/firewire uses filtered physical |
44 | 44 | DMA, hence is not yet suitable for remote debugging. | |
45 | Because these drivers depend on the PCI enumeration to be completed, an | 45 | |
46 | initialization routine which can runs pretty early (long before console_init(), | 46 | Because ohci1394 depends on the PCI enumeration to be completed, an |
47 | initialization routine which runs pretty early (long before console_init() | ||
47 | which makes the printk buffer appear on the console can be called) was written. | 48 | which makes the printk buffer appear on the console can be called) was written. |
48 | 49 | ||
49 | To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: | 50 | To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: |