Re: [PATCH 9/11] Panic delay fix

Pavel Machek
2007-02-07T12:59:19Z

Hi!
> >
> >>Failure to use real-time delay here causes the
> >>keyboard to become demonically
> >>possessed in the event of a kernel crash, with wildly
> >>blinking lights and
> >>unpredictable behavior. This has resulted in several
> >>injuries.
> >
> >There must be a reason why it wasn't default before.
> >Has this
> >reason changed?
>
> This only matters under paravirt; non-paravirt kernels
> and kernels running on native hardware will always
> behave properly.
>
> But paravirtualized kernels with fake devices have no
> need to udelay to accommodate slow hardware - the
> hardware is just virtual. The USE_REAL_TIME_DELAY
> define allows udelay to be specifically reverted back to
> being a real delay. There are only a couple cases where

Ugh, it sounds like paravirt is more b0rken then I thought. It should
always to the proper delay, then replace those udelays that are not
needed on virtualized hardware with something else.

Just magically defining udelay into nop is broken.

Pavel
--
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