Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756131AbYAGWCp (ORCPT ); Mon, 7 Jan 2008 17:02:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753259AbYAGWCh (ORCPT ); Mon, 7 Jan 2008 17:02:37 -0500 Received: from ozlabs.org ([203.10.76.45]:44060 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033AbYAGWCg (ORCPT ); Mon, 7 Jan 2008 17:02:36 -0500 Subject: Re: [RFC] PCIE ASPM support From: Michael Ellerman Reply-To: michael@ellerman.id.au To: Shaohua Li Cc: lkml , linux-pci , Greg KH , "Pallipadi, Venkatesh" In-Reply-To: <1199340944.1642.26.camel@sli10-desk.sh.intel.com> References: <1199340944.1642.26.camel@sli10-desk.sh.intel.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-6xp9A3lq5H/S+SRV7w1x" Date: Tue, 08 Jan 2008 09:02:35 +1100 Message-Id: <1199743355.7518.2.camel@concordia> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3023 Lines: 78 --=-6xp9A3lq5H/S+SRV7w1x Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2008-01-03 at 14:15 +0800, Shaohua Li wrote: > 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. >=20 > This patch adds ASPM support in Linux. It introduces a global policy for > ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control > it. The interface can be used as a boot option too. Currently we have > below setting: > -default, BIOS default setting > -powersave, highest power saving mode, enable all available ASPM state > and clock power management > -performance, highest performance, disable ASPM and clock power > management > By default, the 'default' policy is used currently. >=20 > In my test, power difference between powersave mode and performance mode > is about 1.3w in a system with 3 PCIE links. >=20 > please review, any comments will be appreciated. >=20 > Signed-off-by: Shaohua Li Minor nit, but you do a lot of these: + return ((struct link_state *)pdev->link_state)->bios_aspm_state; + return ((struct link_state *)pdev->link_state)->bios_clk_state; + ((struct link_state*)pdev->link_state)->clk_pm_enabled =3D !!enable; + ((struct link_state*)pdev->link_state)->clk_pm_capable =3D capable; + ((struct link_state*)pdev->link_state)->clk_pm_enabled =3D enabled; + ((struct link_state*)pdev->link_state)->bios_clk_state =3D enabled; + ((struct link_state *)pdev->link_state)->enabled_state =3D state; + if (((struct link_state *)pdev->link_state)->support_state =3D=3D 0) + if (((struct link_state *)pdev->link_state)->enabled_state =3D=3D state) + ((struct link_state *)pdev->link_state)->enabled_state); Which is a little hard on the eye. cheers --=20 Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person --=-6xp9A3lq5H/S+SRV7w1x Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBHgqF7dSjSd0sB4dIRAjHRAJ9p3KHteA3dPt2HHs0iAvEgGJgFYgCgiFEG ylt4LrqnDGto9uvjL9km0ww= =4aGY -----END PGP SIGNATURE----- --=-6xp9A3lq5H/S+SRV7w1x-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/