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authorSteve French <sfrench@us.ibm.com>2008-04-24 15:26:50 +0000
committerSteve French <sfrench@us.ibm.com>2008-04-24 15:26:50 +0000
commit36d99df2fb474222ab47fbe8ae7385661033223b (patch)
tree962e068491b752a944f61c454fad3f8619a1ea3f /Documentation/debugging-via-ohci1394.txt
parent076d8423a98659a92837b07aa494cb74bfefe77c (diff)
parent3dc5063786b273f1aee545844f6bd4e9651ebffe (diff)
Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'Documentation/debugging-via-ohci1394.txt')
-rw-r--r--Documentation/debugging-via-ohci1394.txt16
1 files changed, 10 insertions, 6 deletions
diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt
index c360d4e91b4..59a91e5c690 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.
This can be turned off by ohci1394's module parameter phys_dma=0.
The alternative firewire-ohci driver in drivers/firewire uses filtered physical
-DMA, hence is not yet suitable for remote debugging.
+DMA by default, which is more secure but not suitable for remote debugging.
+Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA (Kernel hacking menu:
+Remote debugging over FireWire with firewire-ohci) to get unfiltered physical
+DMA.
-Because ohci1394 depends on the PCI enumeration to be completed, an
-initialization routine which runs pretty early (long before console_init()
-which makes the printk buffer appear on the console can be called) was written.
+Because ohci1394 and firewire-ohci depend on the PCI enumeration to be
+completed, an initialization routine which runs pretty early has been
+implemented for x86. This routine runs long before console_init() can be
+called, i.e. before the printk buffer appears on the console.
To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu:
-Provide code for enabling DMA over FireWire early on boot) and pass the
-parameter "ohci1394_dma=early" to the recompiled kernel on boot.
+Remote debugging over FireWire early on boot) and pass the parameter
+"ohci1394_dma=early" to the recompiled kernel on boot.
Tools
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