From:   Kazuki <kazukih0205@gmail.com>
Date:   Thu, 9 Feb 2023 00:42:47 +0900
To:     Sudeep Holla <sudeep.holla@arm.com>
Cc:     linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>
Subject: Re: s2idle breaks on machines without cpuidle support
Message-ID: <20230208154247.avb5ol4kyrx3y6mm@kazuki-mac>
References: <20230204152747.drte4uitljzngdt6@kazuki-mac>
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 <20230207194818.exskn3dhyzqwr32v@kazuki-mac>
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 <20230208112031.sdfuluajjerf4wwp@kazuki-mac>
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 <20230208144327.3ftjxnquwhsdykfc@kazuki-mac>
 <20230208150306.ve2pnt3pvlmf5wbu@bogus>
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On Wed, Feb 08, 2023 at 03:34:07PM +0000, Sudeep Holla wrote:
> On Thu, Feb 09, 2023 at 12:19:39AM +0900, Kazuki wrote:
> > On Wed, Feb 08, 2023 at 03:03:06PM +0000, Sudeep Holla wrote:
> 
> [...]
> 
> > > Well, if we are allowing to boot on such a system, then we must allow
> > > adding a platform specific idle driver. It may be useful once we info
> > > to add deeper than WFI states.
> >
> > Hmmm, I thought for arm64, non-PSCI idle drivers were prohibited? Or am
> > I mistaken here?
> 
> I don't know. I am not against it especially now that we have allowed a
> non-PSCI based production system to boot the kernel.
> 
> > > Are we ? I thought were making changes to enable it. Or are you saying
> > > we allow to enter into such a state and render the system unusable, if
> > > so we need to fix it.
> >
> > Both as I mentioned in my first email. Apologies if it turned out to
> > be confusing.
> 
> Sorry still confusing. Are you saying you can enter s2idle and crash or
> hang the system without changes(especially around this s2idle code) ?
Yes.

Thanks,
Kazuki