linux-kernel - Re: [PATCH] powernv:idle: Disable LOSE_FULL

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Message-Id: <20170804170019.GA17813@in.ibm.com>
Date:   Fri, 4 Aug 2017 22:30:19 +0530
From:   Gautham R Shenoy <ego@...ux.vnet.ibm.com>
To:     "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>
Cc:     Michael Ellerman <mpe@...erman.id.au>,
        Michael Neuling <mikey@...ling.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>,
        Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH] powernv:idle: Disable LOSE_FULL_CONTEXT states when
 stop-api fails.

On Fri, Aug 04, 2017 at 12:34:22PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>
> 
> Currently, we use the opal call opal_slw_set_reg() to inform the
> Sleep-Winkle Engine (SLW) to restore the contents of some of the
> Hypervisor state on wakeup from deep idle states that lose full
> hypervisor context (characterized by the flag
> OPAL_PM_LOSE_FULL_CONTEXT).
> 
> However, the current code has a bug in that if opal_slw_set_reg()
> fails, we don't disable the use of these deep states (winkle on
> POWER8, stop4 onwards on POWER9).
> 
> This patch fixes this bug by ensuring that if programing the
> sleep-winkle engine to restore the hypervisor states in
> pnv_save_sprs_for_deep_states() fails, then we exclude such states by
> excluding their flags supported_cpuidle_states. Further, we ensure in
> the initialization of the cpuidle-powernv driver to only include those
> states whose flags are present in supported_cpuidle_states.
> 
> Fixes: 1e1601b38e6 ("powerpc/powernv/idle: Restore SPRs for deep idle
> states via stop API.")
>
Forgot to add

Reported-by: Akshay Adiga <akshay.adiga@...ux.vnet.ibm.com>

> Signed-off-by: Gautham R. Shenoy <ego@...ux.vnet.ibm.com>


--
Thanks and Regards
gautham.