[IA64] Delete: Documentation/ia64/serial.txt

Andrew took the patch that created this, and Linus applied
it to his BK tree.  Remove my copy so that we can merge.
Signed-off-by: Tony Luck <tony.luck@intel.com>

Documentation/ia64/serial.txt

-SERIAL DEVICE NAMING
-
-    As of 2.6.10, serial devices on ia64 are named based on the
-    order of ACPI and PCI enumeration.  The first device in the
-    ACPI namespace (if any) becomes /dev/ttyS0, the second becomes
-    /dev/ttyS1, etc., and PCI devices are named sequentially
-    starting after the ACPI devices.
-
-    Prior to 2.6.10, there were confusing exceptions to this:
-
-	- Firmware on some machines (mostly from HP) provides an HCDP
-	  table[1] that tells the kernel about devices that can be used
-	  as a serial console.  If the user specified "console=ttyS0"
-	  or the EFI ConOut path contained only UART devices, the
-	  kernel registered the device described by the HCDP as
-	  /dev/ttyS0.
-
-	- If there was no HCDP, we assumed there were UARTs at the
-	  legacy COM port addresses (I/O ports 0x3f8 and 0x2f8), so
-	  the kernel registered those as /dev/ttyS0 and /dev/ttyS1.
-
-    Any additional ACPI or PCI devices were registered sequentially
-    after /dev/ttyS0 as they were discovered.
- 
-    With an HCDP, device names changed depending on EFI configuration
-    and "console=" arguments.  Without an HCDP, device names didn't
-    change, but we registered devices that might not really exist.
-
-    For example, an HP rx1600 with a single built-in serial port
-    (described in the ACPI namespace) plus an MP[2] (a PCI device) has
-    these ports:
-
-                                  pre-2.6.10      pre-2.6.10
-                    MMIO         (EFI console    (EFI console
-                   address        on builtin)     on MP port)    2.6.10
-                  ==========      ==========      ==========     ======
-      builtin     0xff5e0000        ttyS0           ttyS1         ttyS0
-      MP UPS      0xf8031000        ttyS1           ttyS2         ttyS1
-      MP Console  0xf8030000        ttyS2           ttyS0         ttyS2
-      MP 2        0xf8030010        ttyS3           ttyS3         ttyS3
-      MP 3        0xf8030038        ttyS4           ttyS4         ttyS4
-  
-CONSOLE SELECTION
-
-    EFI knows what your console devices are, but it doesn't tell the
-    kernel quite enough to actually locate them.  The DIG64 HCDP
-    table[1] does tell the kernel where potential serial console
-    devices are, but not all firmware supplies it.  Also, EFI supports
-    multiple simultaneous consoles and doesn't tell the kernel which
-    should be the "primary" one.
-
-    So how do you tell Linux which console device to use?
-
-	- If your firmware supplies the HCDP, it is simplest to
-	  configure EFI with a single device (either a UART or a VGA
-	  card) as the console.  Then you don't need to tell Linux
-	  anything; the kernel will automatically use the EFI console.
-
-	  (This works only in 2.6.6 or later; prior to that you had
-	  to specify "console=ttyS0" to get a serial console.)
-
-	- Without an HCDP, Linux defaults to a VGA console unless you
-	  specify a "console=" argument.
-
-    NOTE: Don't assume that a serial console device will be /dev/ttyS0.
-    It might be ttyS1, ttyS2, etc.  Make sure you have the appropriate
-    entries in /etc/inittab (for getty) and /etc/securetty (to allow
-    root login).
-
-EARLY SERIAL CONSOLE
-
-    The kernel can't start using a serial console until it knows where
-    the device lives.  Normally this happens when the driver enumerates
-    all the serial devices, which can happen a minute or more after the 
-    kernel starts booting.
-
-    2.6.10 and later kernels have an "early uart" driver that works
-    very early in the boot process.  The kernel will automatically use
-    this if the user supplies an argument like "console=uart,io,0x3f8",
-    or if the EFI console path contains only a UART device and the
-    firmware supplies an HCDP.
-
-TROUBLESHOOTING SERIAL CONSOLE PROBLEMS
- 
-    No kernel output after elilo prints "Uncompressing Linux... done":
-
-	- You specified "console=ttyS0" but Linux changed the device
-	  to which ttyS0 refers.  Configure exactly one EFI console
-	  device[3] and remove the "console=" option.
-
-	- The EFI console path contains both a VGA device and a UART.
-	  EFI and elilo use both, but Linux defaults to VGA.  Remove
-	  the VGA device from the EFI console path[3].
-  
-	- Multiple UARTs selected as EFI console devices.  EFI and
-	  elilo use all selected devices, but Linux uses only one.
-	  Make sure only one UART is selected in the EFI console
-	  path[3].
-
-	- You're connected to an HP MP port[2] but have a non-MP UART
-	  selected as EFI console device.  EFI uses the MP as a
-	  console device even when it isn't explicitly selected.
-	  Either move the console cable to the non-MP UART, or change
-	  the EFI console path[3] to the MP UART.
- 
-    Long pause (60+ seconds) between "Uncompressing Linux... done" and
-    start of kernel output:
- 
-	- No early console because you used "console=ttyS<n>".  Remove
-	  the "console=" option if your firmware supplies an HCDP.
-
-	- If you don't have an HCDP, the kernel doesn't know where
-	  your console lives until the driver discovers serial
-	  devices.  Use "console=uart, io,0x3f8" (or appropriate
-	  address for your machine).
- 
-    Kernel and init script output works fine, but no "login:" prompt:
- 
-	- Add getty entry to /etc/inittab for console tty.  Look for
-	  the "Adding console on ttyS<n>" message that tells you which
-	  device is the console.
- 
-    "login:" prompt, but can't login as root:
- 
-	- Add entry to /etc/securetty for console tty.
- 
-
-
-[1] http://www.dig64.org/specifications/DIG64_PCDPv20.pdf
-    The table was originally defined as the "HCDP" for "Headless
-    Console/Debug Port."  The current version is the "PCDP" for
-    "Primary Console and Debug Port Devices."
-
-[2] The HP MP (management processor) is a PCI device that provides
-    several UARTs.  One of the UARTs is often used as a console; the
-    EFI Boot Manager identifies it as "Acpi(HWP0002,700)/Pci(...)/Uart".
-    The external connection is usually a 25-pin connector, and a
-    special dongle converts that to three 9-pin connectors, one of
-    which is labelled "Console."
-
-[3] EFI console devices are configured using the EFI Boot Manager
-    "Boot option maintenance" menu.  You may have to interrupt the
-    boot sequence to use this menu, and you will have to reset the
-    box after changing console configuration.