Date: Thu, 24 Jan 2008 17:22:58 +0000
From: Pavel Machek <pavel@ucw.cz>
To: Shaohua Li <shaohua.li@intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
       linux-pci <linux-pci@atrey.karlin.mff.cuni.cz>,
       Greg KH <greg@kroah.com>,
       "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
       "Kok, Auke" <auke-jan.h.kok@intel.com>, Matthew Wilcox <matthew@wil.cx>
Subject: Re: [PATCH]PCIE ASPM support - takes 3
Message-ID: <20080124172258.GA5447@ucw.cz>
References: <1200621388.8965.3.camel@sli10-desk.sh.intel.com>
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Hi!

> v3->v2, fixed the issues Matthew Wilcox raised.
> 
> PCI Express ASPM defines a protocol for PCI Express components in the D0
> state to reduce Link power by placing their Links into a low power state
> and instructing the other end of the Link to do likewise. This
> capability allows hardware-autonomous, dynamic Link power reduction
> beyond what is achievable by software-only controlled power management.
> However, The device should be configured by software appropriately.
> Enabling ASPM will save power, but will introduce device latency.

How big is the latency? 1msec? 10msec? 100usec?

-- 
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