Messages in this thread | | | Date | Thu, 30 Apr 2015 09:35:04 -0700 | Subject | Re: regression in ktime.h circa 3.16.0-rc5+ breaks lirc irsend, bad commit 166afb64511 | From | John Stultz <> |
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On Wed, Apr 29, 2015 at 9:27 PM, Trevor Cordes <trevor@tecnopolis.ca> wrote: > Sorry for the top-posting; Josh Boyer suggested I re-mail this mail > from last month which didn't get any replies. I'm still having this > weird kernel bug affecting me and I've bisected it down to like 2-4 > lines of code. (I've thought more about my theory regarding > unsigned/signed below and it's probably wrong, so ignore my > prognosticating.) Please see my rhbz link near the bottom for the full > details.
Thanks so much for the report and all the effort to chase down this regression!
From your description it does seem like some sort of edge case problem w/ the 32bit ktime_divns(), but I don't see it right off, and I agree with Alan to do both calculations and print out warn when that happens.
There's also not a ton of users of that function, but ktime_us_delta() is used in drivers/media/rc/ir-lirc-codec.c, which makes use of it in ir_lirc_transmit_ir().
We should instrument that to see if its calculating negative deltas.
I'll send you a debug patch to do the above.
thanks -john
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