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authorDavid S. Miller <davem@davemloft.net>2008-03-17 23:44:31 -0700
committerDavid S. Miller <davem@davemloft.net>2008-03-17 23:44:31 -0700
commit2f633928cbba8a5858bb39b11e7219a41b0fbef5 (patch)
tree9a82f4b7f2c3afe4b0208d8e44ea61bae90a7d22 /Documentation/debugging-via-ohci1394.txt
parent5e226e4d9016daee170699f8a4188a5505021756 (diff)
parentbde4f8fa8db2abd5ac9c542d76012d0fedab050f (diff)
downloadtalos-obmc-linux-2f633928cbba8a5858bb39b11e7219a41b0fbef5.tar.gz
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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Diffstat (limited to 'Documentation/debugging-via-ohci1394.txt')
-rw-r--r--Documentation/debugging-via-ohci1394.txt17
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).
Drivers
-------
-The OHCI-1394 drivers in drivers/firewire and drivers/ieee1394 initialize
-the OHCI-1394 controllers to a working state and can be used to enable
-physical DMA. By default you only have to load the driver, and physical
-DMA access will be granted to all remote nodes, but it can be turned off
-when using the ohci1394 driver.
-
-Because these drivers depend on the PCI enumeration to be completed, an
-initialization routine which can runs pretty early (long before console_init(),
+The ohci1394 driver in drivers/ieee1394 initializes the OHCI-1394 controllers
+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.
+
+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.
To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu:
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