Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755512AbYGSPj5 (ORCPT ); Sat, 19 Jul 2008 11:39:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754002AbYGSPjt (ORCPT ); Sat, 19 Jul 2008 11:39:49 -0400 Received: from casper.infradead.org ([85.118.1.10]:53840 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbYGSPjs (ORCPT ); Sat, 19 Jul 2008 11:39:48 -0400 Date: Sat, 19 Jul 2008 08:39:42 -0700 From: Arjan van de Ven To: Alan Stern Cc: Kernel development list , USB list Subject: Re: Re [patch 2/3] fastboot: turn the USB hostcontroller initcalls into async initcalls Message-ID: <20080719083942.2daa2959@infradead.org> In-Reply-To: References: Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1690 Lines: 44 On Sat, 19 Jul 2008 11:25:29 -0400 (EDT) Alan Stern wrote: > On 18 July, 2008, Arjan van de Ven wrote: > > > From: Arjan van de Ven > > Subject: [PATCH] fastboot: turn the USB hostcontroller initcalls > > into async initcalls > > > > the USB host controller init calls take a long time, mostly due to a > > "minimally 100 msec" delay *per port* during initialization. > > These are prime candidates for going in parallel to everything else. > > > > The USB device ordering is not affected by this due to the > > serialized-within-eachother property of async initcalls. > > > Where is this "minimally 100 msec" per-port delay you refer to? > Offhand I can't recall any such delays in the init routines. > it's here (in drivers/usb/core/hub.c::hub_power_on): "non-switchable hub\n"); for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++) set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER); /* Wait at least 100 msec for power to become stable */ msleep(max(pgood_delay, (unsigned) 100)); } at least my eeepc901 hits that like 6 or 7 times (because if I shorten the 100 the boot goes a ton faster.. but that's obviously just a bad hack) -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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/