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From: tony@atomide.com (Tony Lindgren)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: OMAP4+: PM: Program CPU logic power state
Date: Mon, 10 Nov 2014 16:03:06 -0800	[thread overview]
Message-ID: <20141111000305.GJ31454@atomide.com> (raw)
In-Reply-To: <7h61f98hvw.fsf@deeprootsystems.com>

* Kevin Hilman <khilman@kernel.org> [141024 11:04]:
> Nishanth Menon <nm@ti.com> writes:
> 
> > CPU logic power state is never programmed in either the initialization
> > or the suspend/resume logic, instead, we depend on mpuss to program this
> > properly. However, this leaves CPU logic power state indeterminate and
> > most probably in reset configuration (If bootloader or other similar
> > software have'nt monkeyed with the register). This can make powerstate=
> > RET be either programmed for CSWR (logic=ret) or OSWR(logic = OFF) and
> > in OSWR, there can be context loss when the code does not expect it.
> >
> > To prevent all these confusions, just support clearly ON, INA, CSWR,
> > OFF which is the intent of the existing code by explicitly programming
> > logic state.
> >
> > NOTE: since this is a hot path (using in cpuidle), the exit path just
> > programs powerstate (logic state is immaterial when powerstate is ON).
> >
> > Without doing this, we end up with lockups when CPUs enter OSWR and
> > multiple blocks loose context, when we expect them to hit CSWR.
> >
> > Signed-off-by: Nishanth Menon <nm@ti.com>
> 
> Acked-by: Kevin Hilman <khilman@linaro.org>

Applying into omap-for-v3.19/soc thanks.

Tony

      reply	other threads:[~2014-11-11  0:03 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-21 20:24 [PATCH] ARM: OMAP4+: PM: Program CPU logic power state Nishanth Menon
2014-10-24 18:03 ` Kevin Hilman
2014-11-11  0:03   ` Tony Lindgren [this message]

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