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From: Pavel Machek <pavel@ucw.cz>
To: shiva.linuxworks@gmail.com
Cc: rjw@rjwysocki.net, len.brown@intel.com, linux-pm@vger.kernel.org,
	kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me,
	linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	Shivamurthy Shastri <sshivamurthy@micron.com>,
	Keith Busch <kbush@kernel.org>
Subject: Re: [PATCH v2 1/2] PM: enable support for imminent power loss
Date: Mon, 26 Jul 2021 21:41:46 +0200	[thread overview]
Message-ID: <20210726194146.GA3986@localhost> (raw)
In-Reply-To: <20210726132223.1661-2-sshivamurthy@micron.com>

Hi!

> If the shutdown is pwerformed when the platform is running on the
> limited backup power supply, some of the devices might not have enough
> power to perform a clean shutdown.
> 
> It is necessary to inform the driver about the limited backup power
> supply, to allow the driver to decide to perform the minimal required
> operation for a fast and clean shutdown.

If you can do shutdown that is fast & clean, why not do it always?

How fast is normal shutdown vs. fast shutdown?

> +#define PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT	BIT(3)

I believe we should be more concrete here. Like explaining use (did
UPS say battery is low? Or does it mean 10 seconds remaining? Or...?)

Plus, who sets this flag? Userland?

Best regards,
								Pavel


-- 

WARNING: multiple messages have this Message-ID (diff)
From: Pavel Machek <pavel@ucw.cz>
To: shiva.linuxworks@gmail.com
Cc: rjw@rjwysocki.net, len.brown@intel.com, linux-pm@vger.kernel.org,
	kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me,
	linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	Shivamurthy Shastri <sshivamurthy@micron.com>,
	Keith Busch <kbush@kernel.org>
Subject: Re: [PATCH v2 1/2] PM: enable support for imminent power loss
Date: Mon, 26 Jul 2021 21:41:46 +0200	[thread overview]
Message-ID: <20210726194146.GA3986@localhost> (raw)
In-Reply-To: <20210726132223.1661-2-sshivamurthy@micron.com>

Hi!

> If the shutdown is pwerformed when the platform is running on the
> limited backup power supply, some of the devices might not have enough
> power to perform a clean shutdown.
> 
> It is necessary to inform the driver about the limited backup power
> supply, to allow the driver to decide to perform the minimal required
> operation for a fast and clean shutdown.

If you can do shutdown that is fast & clean, why not do it always?

How fast is normal shutdown vs. fast shutdown?

> +#define PM_SUSPEND_FLAG_POWER_LOSS_IMMINENT	BIT(3)

I believe we should be more concrete here. Like explaining use (did
UPS say battery is low? Or does it mean 10 seconds remaining? Or...?)

Plus, who sets this flag? Userland?

Best regards,
								Pavel


-- 

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  reply	other threads:[~2021-07-26 19:41 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26 13:22 [PATCH v2 0/2] Abrupt Shutdown for NVMe SSD shiva.linuxworks
2021-07-26 13:22 ` shiva.linuxworks
2021-07-26 13:22 ` [PATCH v2 1/2] PM: enable support for imminent power loss shiva.linuxworks
2021-07-26 13:22   ` shiva.linuxworks
2021-07-26 19:41   ` Pavel Machek [this message]
2021-07-26 19:41     ` Pavel Machek
2021-07-26 20:16     ` Keith Busch
2021-07-26 20:16       ` Keith Busch
2021-07-26 13:22 ` [PATCH v2 2/2] nvme: Add abrupt shutdown support shiva.linuxworks
2021-07-26 13:22   ` shiva.linuxworks
2021-07-26 16:07   ` kernel test robot
2021-07-26 16:07     ` kernel test robot
2021-07-26 16:07     ` kernel test robot
2021-07-26 16:43   ` kernel test robot
2021-07-26 16:43     ` kernel test robot
2021-07-26 16:43     ` kernel test robot
2021-07-26 15:24 ` [PATCH v2 0/2] Abrupt Shutdown for NVMe SSD Keith Busch
2021-07-26 15:24   ` Keith Busch
2021-07-29 10:37   ` [EXT] " Shivamurthy Shastri (sshivamurthy)
2021-07-29 10:37     ` Shivamurthy Shastri (sshivamurthy)

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