From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758089AbZAGRYS (ORCPT ); Wed, 7 Jan 2009 12:24:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753473AbZAGRX6 (ORCPT ); Wed, 7 Jan 2009 12:23:58 -0500 Received: from casper.infradead.org ([85.118.1.10]:44927 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753021AbZAGRX5 (ORCPT ); Wed, 7 Jan 2009 12:23:57 -0500 Date: Wed, 7 Jan 2009 09:25:55 -0800 From: Arjan van de Ven To: Yong Wang Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, mingo@elte.hu, akpm@linux-foundation.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH 4/6] fastboot: make ACPI bus drivers probe asynchronous Message-ID: <20090107092555.6e89e9c7@infradead.org> In-Reply-To: <20090107141256.GA22902@ywang-moblin2.bj.intel.com> References: <20090105200959.04a626ac@infradead.org> <20090105201239.0784606e@infradead.org> <20090107141256.GA22902@ywang-moblin2.bj.intel.com> Organization: Intel X-Mailer: Claws Mail 3.6.1 (GTK+ 2.14.5; 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 On Wed, 7 Jan 2009 22:12:56 +0800 Yong Wang wrote: > On Mon, Jan 05, 2009 at 08:12:39PM -0800, Arjan van de Ven wrote: > > > > >From 34c47dd38f49e29eb7cd7fa2078efc6b8b258bb9 Mon Sep 17 00:00:00 > > >2001 > > From: Arjan van de Ven > > Date: Sun, 4 Jan 2009 05:32:28 -0800 > > Subject: [PATCH] fastboot: make ACPI bus drivers probe asynchronous > > > > the various ACPI bus drivers have non-overlapping devices and can > > each be run asynchronous. Some of the ACPI drivers (especially the > > battery one, but others as well) can take quite a long time to > > probe. > > > > Signed-off-by: Arjan van de Ven > > --- > > drivers/acpi/scan.c | 23 ++++++++++++++++------- > > 1 files changed, 16 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c > > index 39b7233..a9e542d 100644 > > --- a/drivers/acpi/scan.c > > +++ b/drivers/acpi/scan.c > > @@ -8,6 +8,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include /* for > > acpi_ex_eisa_id_to_string() */ @@ -578,6 +579,19 @@ static int > > acpi_start_single_object(struct acpi_device *device) return result; > > } > > > > +static void acpi_bus_register_async(void *data, async_cookie_t > > cookie) +{ > > + int ret; > > + struct acpi_driver *driver = data; > > + driver->drv.name = driver->name; > > + driver->drv.bus = &acpi_bus_type; > > + driver->drv.owner = driver->owner; > > + > > + async_synchronize_cookie(cookie); > > + > > + ret = driver_register(&driver->drv); > > + WARN_ON(ret != 0); > > +} > > /** > > * acpi_bus_register_driver - register a driver with the ACPI bus > > * @driver: driver being registered > > @@ -588,16 +602,11 @@ static int acpi_start_single_object(struct > > acpi_device *device) */ > > int acpi_bus_register_driver(struct acpi_driver *driver) > > { > > - int ret; > > > > if (acpi_disabled) > > return -ENODEV; > > - driver->drv.name = driver->name; > > - driver->drv.bus = &acpi_bus_type; > > - driver->drv.owner = driver->owner; > > - > > - ret = driver_register(&driver->drv); > > - return ret; > > + async_schedule(acpi_bus_register_async, driver); > > + return 0; > > } > > > > EXPORT_SYMBOL(acpi_bus_register_driver); > > For ACPI battery, button and thermal drivers whose init funtion > immediately ends right after calling acpi_bus_register_driver, it > might be OK. But for other drivers whose init function has more work > to do and depends on acpi_bus_register_driver having *really* done > its job, it is certainly not OK. In the latter case, the 'return 0' > in acpi_bus_register_driver is effectively cheating those drivers > that acpi_bus_register_driver has already done its job which is > unfortunately not the case. Example drivers include eeepc_laptop and > asus_laptop. At least I am seeing a kernel oops on eeepc because of > that. ok I've dropped the ACPI part for now; I'll work with you and Len to see how we can solve the ACPI side, but for now it seems to have too many issues > > -Yong -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org