vt.handoff uses kernel-internal numbering, not conventional user-visible numbering

[Colin Watson]

(Background: vt.handoff is a module parameter introduced in an Ubuntu-specific SAUCE patch by Andy Whitcroft, currently 317a108ec14826f15e7dbf811ccabed475d4fd20 in git. It was written expressly for use in the Ubuntu boot process, but we have not started using it yet. While experimenting with getting that up and running, I found this bug. Triagers: I'm not including the usual log files here because they aren't relevant.)

vt.handoff is interpreted in terms of kernel VT numbering, which is 0-based. However, the normal user-visible numbering is 1-based. This means that if you want to nominate VT 7 as a transparent VT, you must say vt.handoff=6. I think this is confusing, and that before we start using this feature widely we should fix the numbering.

In support, I note that even Andy gets this wrong right now. :-) When we were talking about this feature, he was saying that vt.handoff=8 should cause VT 8 to be used as a transparent VT.

[Andy Whitcroft (apw)]

Yes all of the other user visible interfaces consume VT numbers starting at 1 and adjust to kernel numbering internally. We should be doing the same for this control.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 2.6.37-9.23

---------------
linux (2.6.37-9.23) natty; urgency=low

  [ Andy Whitcroft ]

  * SAUCE: vt -- fix handoff numbering to 1..n and add range checks
    - LP: #689606
  * SAUCE: vt -- fix handoff numbering to 1..n and add range checks (grub)
    - LP: #689606

  [ Kees Cook ]

  * SAUCE: RO/NX protection for loadable kernel, fix ftrace
    - LP: #690190
 -- Andy Whitcroft <email address hidden> Wed, 15 Dec 2010 19:29:57 +0000