Maybe the 1ms threshold thing is just to do with a threshold heuristic
where it stops using the scheduler and sleeping and instead spins
udelay() style, hence the 100% CPU.  That's not to write off its effect
on the bug just a possible explanation of why it cares about 1ms or
less.

Reading these new findings yesterday and today I wonder if it's somehow
related to when the ehci stuff schedules the URB.  Like if the CPU is
totally up it can pack USB transactions to go out immediately, but
somehow when "idle", although what exactly is in what kind of idle is
unclear, it bumps it to the next frame or so.

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Title:
  panda: USB disk IO slow

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