diff options
Diffstat (limited to 'Documentation/debugging-via-ohci1394.txt')
-rw-r--r-- | Documentation/debugging-via-ohci1394.txt | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt index c360d4e91b48..59a91e5c6909 100644 --- a/Documentation/debugging-via-ohci1394.txt +++ b/Documentation/debugging-via-ohci1394.txt | |||
@@ -41,15 +41,19 @@ to a working state and enables physical DMA by default for all remote nodes. | |||
41 | This can be turned off by ohci1394's module parameter phys_dma=0. | 41 | This can be turned off by ohci1394's module parameter phys_dma=0. |
42 | 42 | ||
43 | The alternative firewire-ohci driver in drivers/firewire uses filtered physical | 43 | The alternative firewire-ohci driver in drivers/firewire uses filtered physical |
44 | DMA, hence is not yet suitable for remote debugging. | 44 | DMA by default, which is more secure but not suitable for remote debugging. |
45 | Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA (Kernel hacking menu: | ||
46 | Remote debugging over FireWire with firewire-ohci) to get unfiltered physical | ||
47 | DMA. | ||
45 | 48 | ||
46 | Because ohci1394 depends on the PCI enumeration to be completed, an | 49 | Because ohci1394 and firewire-ohci depend on the PCI enumeration to be |
47 | initialization routine which runs pretty early (long before console_init() | 50 | completed, an initialization routine which runs pretty early has been |
48 | which makes the printk buffer appear on the console can be called) was written. | 51 | implemented for x86. This routine runs long before console_init() can be |
52 | called, i.e. before the printk buffer appears on the console. | ||
49 | 53 | ||
50 | To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: | 54 | To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: |
51 | Provide code for enabling DMA over FireWire early on boot) and pass the | 55 | Remote debugging over FireWire early on boot) and pass the parameter |
52 | parameter "ohci1394_dma=early" to the recompiled kernel on boot. | 56 | "ohci1394_dma=early" to the recompiled kernel on boot. |
53 | 57 | ||
54 | Tools | 58 | Tools |
55 | ----- | 59 | ----- |