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>

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: