Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757440Ab2KCQfs (ORCPT ); Sat, 3 Nov 2012 12:35:48 -0400 Received: from netrider.rowland.org ([192.131.102.5]:54785 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757245Ab2KCQfo (ORCPT ); Sat, 3 Nov 2012 12:35:44 -0400 Date: Sat, 3 Nov 2012 12:35:43 -0400 (EDT) From: Alan Stern X-X-Sender: stern@netrider.rowland.org To: Linus Torvalds cc: "Rafael J. Wysocki" , Linux Kernel Mailing List , Linux PM list , Greg Kroah-Hartman Subject: Re: Linux 3.7-rc3 In-Reply-To: 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: 1491 Lines: 35 On Fri, 2 Nov 2012, Linus Torvalds wrote: > On Fri, Nov 2, 2012 at 3:43 PM, Rafael J. Wysocki wrote: > > > > Well, not everything is rosy in the suspend land, though. This is a > > failure to freeze khubd during the second in a row attempt to suspend to > > RAM (your current tree): > > Ugh. So khubd is blocked in usb_start_wait_urb(), and apparently the > timeout for that block is longer than the freezing timeout. > > There's a comment about why khubd needs to be freezable, but I wonder > if that whole thing isn't doing something wrong. Causing the suspend > to fail is definitely always the wrong thing. khubs has been a potential problem for suspend since the beginning. The USB spec mandates timeouts of 5 seconds. In addition, khubd does lots of retries when errors occur (probably way too many) and checks for freezability only when its to-do list is empty. Under normal circumstances this isn't a problem. Issues arise when a non-cooperative device is plugged in shortly before a suspend starts. I suppose we could scatter a whole bunch of checks at spots throughout the device-initialization code. This seems awkward but I can't think of anything better. Does anyone have other suggestions? 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/