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Documentation: correction to debugging-via-ohci1394 

Rectify a factoid about firewire-ohci.

Acked-by: Ingo Molnar <mingo@elte.hu>

Also fix a typo spotted by Bernhard Kaindl.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter 2008-02-18 21:38:35 +01:00
parent ef774c16a7
commit 09d7328e62
1 changed files with 8 additions and 7 deletions
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15
Documentation/debugging-via-ohci1394.txt
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@ -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.
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.
Because these drivers depend on the PCI enumeration to be completed, an
initialization routine which can runs pretty early (long before console_init(),
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: