[Skiboot] [PATCH 2/2] core/fast-reset: Do not enable by default

Michael Ellerman mpe at ellerman.id.au
Mon Feb 24 13:08:29 AEDT 2020

Oliver O'Halloran <oohall at gmail.com> writes:

> Fast reboot started life as a debug hack and it escaped into the wild when
> Stewart enabled it by default. There was some reasons for this, but the
> main one is that a full reboot takes somewhere between one and five
> minutes. For those of us who spend all day rebooting their POWER systems
> this is great, but the utility for end users has always been pretty
> questionable.
> Rebooting a system should be a fairly infrequent activity in the field
> with the main reasons for doing one being:
> 1) Kernel updates,
> 2) Misbehaving hardware
> Although 1) can be performed by kexec we have found that it fails due to
> 2) occasionally. The reason for 2) is usually hardware getting itself
> into a bad state. The universal fix for that type of hardware problem
> is turning the hardware off and back on again so it's preferable that
> a reboot actually does that.
> This patch refactors the reboot handling OPAL calls so that fast-reboot
> is only used by default when explicitly enabled, or manually invoked.
> This allows developers to continue to use fast-reboot without expecting
> users deal with its quirks (and understand how a "normal" reboot,
> fast-reboot and MPIPL differ).

+(infinite points)


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