Messages in this thread | | | From | Andrew Lutomirski <> | Date | Wed, 10 Nov 2010 15:06:07 -0500 | Subject | Re: Severe reproducible nouveau breakage in 2.6.36 (and maybe .35) |
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On Wed, Nov 10, 2010 at 2:28 PM, Andrew Lutomirski <andy@luto.us> wrote: > Hi all- > > Somewhere between 2.6.34-fedora-whatever and 2.6.36, Nouveau became > extremely broken on my hardware. It appears to be triggered by a bug > in my monitor (HP LP2475w), which causes the monitor to disappear from > DVI when it goes to sleep. Every time the console blanks (in X or > otherwise AFAICT) the system crashes oddly but unrecoverably. This is > 100% reproducible by Ctrl-Alt-F2 followed by 'echo 1 >>/sys/class/graphics/fb0/blank' *from SSH* and waiting a few seconds > for the monitor to go to sleep, but it also happens if I just walk > away from the computer long enough for it to blank itself. This is > present on F14's kernel and on 2.6.36 from kernel.org. This may or > may not be related to the unreproducible crashes that I used to get > rarely on 2.6.34.
> > The best hint I have is from this patch (sorry for whitespace damage): >
> > which spews "nv50 got hpd irq" once the display blanks.
I tracked it down. The interrupt code in 2.6.36 is totally broken --- it acknowledges the interrupt *in the bottom half*. This might work by accident if the bottom half gets queued on a different CPU, but something probably changed (concurrency-managed workqueues?) that make the BH end up on the same cpu. So the cpu starves the BH and there goes a cpu.
Then the clocksource watchdog hits and takes the whole system down when it calls stop_machine, which also gets starved on that cpu.
Patch coming.
--Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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