Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261560AbUJ0C0z (ORCPT ); Tue, 26 Oct 2004 22:26:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261570AbUJ0C0z (ORCPT ); Tue, 26 Oct 2004 22:26:55 -0400 Received: from jpnmailout02.yamato.ibm.com ([203.141.80.82]:7150 "EHLO jpnmailout02.yamato.ibm.com") by vger.kernel.org with ESMTP id S261560AbUJ0C0x (ORCPT ); Tue, 26 Oct 2004 22:26:53 -0400 In-Reply-To: <1098842129.12477.2.camel@sli10-desk.sh.intel.com> Subject: Re: [ACPI] [Proposal]Another way to save/restore PCI config space for suspend/resume To: Li Shaohua Cc: ACPI-DEV , greg@kroah.com, Len Brown , lkml , Pavel Machek X-Mailer: Lotus Notes Release 6.0.2CF2 July 23, 2003 Message-ID: From: Hiroshi 2 Itoh Date: Wed, 27 Oct 2004 11:26:40 +0900 X-MIMETrack: Serialize by Router on D19ML115/19/M/IBM(Release 6.51HF338 | June 21, 2004) at 2004/10/27 11:26:40 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1745 Lines: 47 > > > > I think a basic problem of current Linux device model is that there is no > > effective message path from sibling devices to their root device. > > Although the message direction from a root device to sibling devices is > > natural from the viewpoint of device enumeration, the direction from > > sibling devices to a root device is required for effective arbitration for > > device configuration and power management. > > > > The Windows driver model uses the direction from sibling drivers to a root > > bus driver mainly, i.e. sibling drivers are layered on a root bus driver. > > While we need a kind of callback mechanism from PCI (sibling) devices to > > PCI bus (root) device instead because their normal call interface is from a > > root device to sibling devices. > Hiro-san, > I don't really understand why this is related with suspend/resume. Could > you please explain it more clearly? > Hi, What I mean is that: There are some bridge devices to be supported by a driver for various device types and vendors. In the long run PCI drivers will have power dependency one another in the long run. It is natual that PCI bridge driver reports its child devices and their dependency to PCI core because PCI core driver needs to know power up/down sequence at suspend/resume time. So I think callbacks from bridge-to-core is useful. Especially it is more useful for the core to get exact timing to power up the next driver if some devices have certain latency to power up. - Hiro. - 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/