** Description changed:

  In all kernels since 2.6.39, the "irqfixup" and "irqpoll" options are no
- longer taking effect.  I have several machines that need to boot with
- one of these options, and I see reports of this regression from multiple
- other users.
+ 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, and this is the commit where the regression
- arrives:
+ through the patches, isolated two regressions, and submitted patches for
+ each.
  
-   commit d05c65fff0
+ 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
  
- I have a patch that fixes most of my machones, and the maintainer has
- accepted it:
+ The maintainer has accepted my patch for that, and it will be in Linux
+ 3.2.  I'm keeping an eye on the stable tree.  At this point, I'd ask
+ Ubuntu to apply it.  It's attached here, and is in Linus' tree at:
  
-   https://lkml.org/lkml/2011/11/2/260
+ 
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:
  
- Any testing of the current patch would be great.
- 
- I wish I could say that's the end of it, but I have found configurations
- on my machines where a bad irq still goes uncaught, even with my patch.
- 
- Focusing on those cases, it comes down to this patch:
- 
-   commit fa27271bc , genirq: Fixup poll handling
+   commit fa27271bc , genirq: Fixup poll handling
  
  
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=fa27271bc8d230355c1f24ddea103824fdc12de6
  
- This patch changes the approach in multiple ways, and I haven't figured
- out where it drops the ball.  I've toyed around with the changes, but
- have not produced a clear fix.  I'll keep trying, and will be in touch
- with the maintainer again.
+ 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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https://bugs.launchpad.net/bugs/855199

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

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