From: Tejun Heo <tj@kernel.org>
To: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: hdegoede@redhat.com, rjw@rjwysocki.net, alan.cox@intel.com,
linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org, Mario.Limonciello@dell.com
Subject: Re: [RFC PATCH] ata: ahci: Enable DEVSLP by default on x86 modern standby platform
Date: Mon, 2 Jul 2018 13:21:51 -0700 [thread overview]
Message-ID: <20180702202151.GK533219@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20180702190845.7456-1-srinivas.pandruvada@linux.intel.com>
On Mon, Jul 02, 2018 at 12:08:45PM -0700, Srinivas Pandruvada wrote:
> From: Srinivas <srinivas.pandruvada@linux.intel.com>
>
> One of the requirement for modern x86 system to enter lowest power mode
> (SLP_S0) is SATA IP block to be off. This is true even during when
> platform is suspended to idle and not only in opportunistic (runtime)
> suspend.
>
> Several of these system don't have traditional ACPI S3, so it is
> important that they enter SLP_S0 state, to avoid draining battery even
> during suspend even with out of the box Linux installation.
>
> SATA IP block doesn't get turned off till SATA is in DEVSLP mode. Here
> user has to either use scsi-host sysfs or tools like powertop to set
> the sata-host link_power_management_policy to min_power.
>
> This change sets by default link power management policy to min_power
> for some platforms. To avoid regressions, the following conditions
> are used:
> - The kernel config is already set to use med_power_with_dipm or deeper
> - System is a modern standby system using ACPI low power idle flag
> - The platform is not blacklisted for Suspend to Idle and suspend
> to idle is used instead of S3
> This combination will make sure that systems are fairly recent and
> since getting shipped with modern standby standby, the DEVSLP function
> is already validated.
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Seems sane to me. Hans, what do you think?
Thanks.
--
tejun
next prev parent reply other threads:[~2018-07-02 20:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-02 19:08 [RFC PATCH] ata: ahci: Enable DEVSLP by default on x86 modern standby platform Srinivas Pandruvada
2018-07-02 20:21 ` Tejun Heo [this message]
2018-07-02 21:27 ` Hans de Goede
2018-07-02 22:08 ` Srinivas Pandruvada
2018-07-02 22:56 ` Mario.Limonciello
2018-07-03 8:57 ` Hans de Goede
2018-07-03 10:21 ` Hans de Goede
2018-07-06 0:52 ` Srinivas Pandruvada
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