mythbuntu-bugs team mailing list archive

["Herton R. Krzesinski" <855199@xxxxxxxxxxxxxxxxxx>]

The commit c75d720fca8a91ce99196d33adea383621027bf2, cherry-picked into
oneiric, is an early application of a change that will be coming in via
upstream stable. As such it is not subject to the standard bug
verification process.

** Tags added: verification-done-oneiric

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https://bugs.launchpad.net/bugs/855199

Title:
  "irqfixup" and "irqpoll" broken since 2.6.39

Status in The Linux Kernel:
  Confirmed
Status in Mythbuntu, Ubuntu derivative focused upon MythTV:
  Confirmed
Status in “linux” package in Ubuntu:
  Fix Released
Status in “linux” source package in Oneiric:
  Fix Committed
Status in “linux” source package in Precise:
  Fix Released

Bug description:
  In all kernels since 2.6.39, the "irqfixup" and "irqpoll" options are
  no longer taking effect.

  The interrupts now generate the same errors seen without these kernel
  options, e.g.:

    irq 19: nobody cared (try booting with the "irqpoll" option)

  even though irqpoll, or irqfixup, is used.

  The Linux irq code was reworked during the 2.6.39 cycle.  I have gone
  through the patches, isolated two regressions, and submitted patches
  for each.

  The first bug effectively disabled the bad-irq handling routines, by a
  test condition be accidentally reversed.  This is the commit where the
  regression arrives:

    commit d05c65fff0 , genirq: spurious: Run only one poller at a time

  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=d05c65fff0ef672be75429266751f0e015b54d94

  The maintainer has accepted my patch for that, and it's on its way
  into releases: it will be in Linux 3.2, and upcoming stable releases,
  likely 3.0.11 and 3.1.3.  And it's marked as committed to Oneirc now.
  It's attached here, and is in Linus' tree at:

  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commit;h=c75d720fca8a91ce99196d33adea383621027bf2

  That bug disabled irqfixup & irqpoll for everybody.  But with that
  fixed, I had some machines where those kernel options still failed.  I
  bisected that problem to here:

    commit fa27271bc , genirq: Fixup poll handling

  http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=fa27271bc8d230355c1f24ddea103824fdc12de6

  I've just submitted another patch, for that regression. (So far, no
  one else seeing this bug report has hit that second regression, so
  there may be no one here in a position to test it.  I have found a
  previous post to LKML, from a user who bisected his problem to the
  same commit, fa2727, so I may try to contact him:
  https://lkml.org/lkml/2011/7/24/54 .)

  At any rate, my second submission to Thomas can be watched here:

    https://lkml.org/lkml/2011/11/19/189

  And I'll report back.

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