Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751554Ab1CJDdT (ORCPT ); Wed, 9 Mar 2011 22:33:19 -0500 Received: from netrider.rowland.org ([192.131.102.5]:38705 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750981Ab1CJDdS (ORCPT ); Wed, 9 Mar 2011 22:33:18 -0500 Date: Wed, 9 Mar 2011 22:33:17 -0500 (EST) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: "Rafael J. Wysocki" cc: LKML , Greg KH , Jesse Barnes , , "H. Peter Anvin" , Kay Sievers , Linux PM mailing list , Subject: Re: [linux-pm] [RFC][PATCH 1/2] Introduce struct syscore_ops and related functionality In-Reply-To: <201103100133.06734.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2076 Lines: 60 On Thu, 10 Mar 2011, Rafael J. Wysocki wrote: > Some subsystems need to carry out suspend/resume and shutdown > operations with one CPU on-line and interrupts disabled. The only > way to register such operations is to define a sysdev class and > a sysdev specifically for this purpose which is cumbersome and > inefficient. Moreover, the arguments taken by sysdev suspend, > resume and shutdown callbacks are practically never necessary. > > For this reason, introduce a simpler interface allowing subsystems > to register operations to be executed very late during system suspend > and shutdown and very early during resume in the form of > strcut syscore_ops objects. ... > Index: linux-2.6/drivers/base/syscore.c > =================================================================== > --- /dev/null > +++ linux-2.6/drivers/base/syscore.c It's true that the existing sys.c file lies in drivers/base; this is presumably because it handles a bunch of class-related registration stuff. Now you're getting rid of all that, leaving just the power-related operations, so doesn't it make more sense to put this file in drivers/base/power? > +/** > + * syscore_suspend - Execute all the registered system core suspend callbacks. > + * > + * This function is executed with one CPU on-line and disabled interrupts. > + */ > +int syscore_suspend(void) > +{ > + struct syscore_ops *ops; > + > + list_for_each_entry_reverse(ops, &syscore_ops_list, node) > + if (ops->suspend) { > + int ret = ops->suspend(); > + if (ret) { > + pr_err("PM: System core suspend callback " > + "%pF failed.\n", ops->suspend); > + return ret; If an error occurs, you need to go back and resume all the things that were suspended. At least, that's what the code in sysdev_suspend does. > + } > + } > + > + return 0; > +} Alan Stern -- 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/