Bug#504878: Support for 3215 console in zipl

[zlinuxman@wowway.com]

Package: s390-tools
Version: 1.6.2-1
Severity: wishlist

Currently, zipl has no support for a 3215 console.  It always uses the
integrated system console (SCLP) for both input and output.  This works
OK when running directly in a logical partition (LPAR), but not so well
when running in a virtual machine under z/VM.  Output to the integrated
system console is redirected to the terminal by CP, but input from the
integrated system console is another story.  To select option 2 from the
boot menu, for example, when running in an LPAR, the user need only type

2

and press Enter on the "Operating System Messages" window.  But when
running in a virtual machine under z/VM, the user must type

#CP VINPUT VMSG 2

and press Enter to select option 2 from the boot menu.  Even if the user
knows what to do, typing all of that in ten seconds or less (the default
boot wait time) can be a real challenge.

zipl should scan the subchannels in ascending sequence by subchannel number
looking for a 3215 device.  The first one found should be used as the
console.  If no 3215 device is found, then the integrated system console
(SCLP) should be used as the console.  That will allow consistent behavior
between an LPAR and a virtual machine.  The user will simply need to type

2

and press Enter to select option 2 from the boot menu, regardless of whether
he is running in an LPAR or a virtual machine.
  

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