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Commit 07e846ba authored by Randy Dunlap's avatar Randy Dunlap Committed by Ingo Molnar
Browse files

x86/doc: Fix Documentation/x86/earlyprintk.txt 



Fix a few issues in Documentation/x86/earlyprintk.txt:

- correct typos, punctuation, missing word, wrong word
- change product name from Netchip to NetChip
- expand where to add "earlyprintk=dbg"

Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Link: http://lkml.kernel.org/r/d0c40ac3-7659-6374-dbda-23d3d2577f30@infradead.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 11da3a7f

Documentation/x86/earlyprintk.txt

+15 −10
Original line number Diff line number Diff line
@@ -35,25 +35,25 @@ and two USB cables, connected like this: 
( If your system does not list a debug port capability then you probably

  won't be able to use the USB debug key. )



 b.) You also need a Netchip USB debug cable/key:

 b.) You also need a NetChip USB debug cable/key:



        http://www.plxtech.com/products/NET2000/NET20DC/default.asp



     This is a small blue plastic connector with two USB connections,

     This is a small blue plastic connector with two USB connections;

     it draws power from its USB connections.



 c.) You need a second client/console system with a high speed USB 2.0

     port.



 d.) The Netchip device must be plugged directly into the physical

 d.) The NetChip device must be plugged directly into the physical

     debug port on the "host/target" system.  You cannot use a USB hub in

     between the physical debug port and the "host/target" system.



     The EHCI debug controller is bound to a specific physical USB

     port and the Netchip device will only work as an early printk

     port and the NetChip device will only work as an early printk

     device in this port.  The EHCI host controllers are electrically

     wired such that the EHCI debug controller is hooked up to the

     first physical and there is no way to change this via software.

     first physical port and there is no way to change this via software.

     You can find the physical port through experimentation by trying

     each physical port on the system and rebooting.  Or you can try

     and use lsusb or look at the kernel info messages emitted by the
@@ -65,9 +65,9 @@ and two USB cables, connected like this: 
     to the hardware vendor, because there is no reason not to wire

     this port into one of the physically accessible ports.



 e.) It is also important to note, that many versions of the Netchip

 e.) It is also important to note, that many versions of the NetChip

     device require the "client/console" system to be plugged into the

     right and side of the device (with the product logo facing up and

     right hand side of the device (with the product logo facing up and

     readable left to right).  The reason being is that the 5 volt

     power supply is taken from only one side of the device and it

     must be the side that does not get rebooted.
@@ -81,13 +81,18 @@ and two USB cables, connected like this: 
      CONFIG_EARLY_PRINTK_DBGP=y



    And you need to add the boot command line: "earlyprintk=dbgp".



    (If you are using Grub, append it to the 'kernel' line in

     /etc/grub.conf)

     /etc/grub.conf.  If you are using Grub2 on a BIOS firmware system,

     append it to the 'linux' line in /boot/grub2/grub.cfg. If you are

     using Grub2 on an EFI firmware system, append it to the 'linux'

     or 'linuxefi' line in /boot/grub2/grub.cfg or

     /boot/efi/EFI/<distro>/grub.cfg.)



    On systems with more than one EHCI debug controller you must

    specify the correct EHCI debug controller number.  The ordering

    comes from the PCI bus enumeration of the EHCI controllers.  The

    default with no number argument is "0" the first EHCI debug

    default with no number argument is "0" or the first EHCI debug

    controller.  To use the second EHCI debug controller, you would

    use the command line: "earlyprintk=dbgp1"
@@ -111,7 +116,7 @@ and two USB cables, connected like this: 
    see the raw output.



 c.) On Nvidia Southbridge based systems: the kernel will try to probe

     and find out which port has debug device connected.

     and find out which port has a debug device connected.



3. Testing that it works fine: