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Commit 09d7328e authored by Stefan Richter's avatar Stefan Richter
Browse files

Documentation: correction to debugging-via-ohci1394 



Rectify a factoid about firewire-ohci.

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

Also fix a typo spotted by Bernhard Kaindl.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent ef774c16

Documentation/debugging-via-ohci1394.txt

+9 −8
Original line number Diff line number Diff line
@@ -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: