From mboxrd@z Thu Jan 1 00:00:00 1970 From: Holger Macht Subject: Re: [PATCH] ACPI: dock: Don't eval _STA on every show_docked sysfs read Date: Fri, 06 Feb 2009 17:47:56 +0100 Message-ID: <1233938876.12590.4.camel@homac.suse.de> References: <1232450304.5286.4.camel@homac.suse.de> <20090127130455.2c1b0cd4.akpm@linux-foundation.org> Reply-To: hmacht@suse.de Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=-BS20JcaEHnzBbJejXpBQ" Return-path: Received: from mail.suse.de ([195.135.220.2]:53908 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbZBFQsM (ORCPT ); Fri, 6 Feb 2009 11:48:12 -0500 In-Reply-To: <20090127130455.2c1b0cd4.akpm@linux-foundation.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Andrew Morton Cc: linux-acpi@vger.kernel.org, stable@kernel.org, lenb@kernel.org, Li@suse.de, shaohua.li@intel.com, marvin@mydatex.cz --=-BS20JcaEHnzBbJejXpBQ Content-Type: text/plain Content-Transfer-Encoding: 7bit Hi, sorry for the delay... On Tue, 2009-01-27 at 13:04 -0800, Andrew Morton wrote: > On Tue, 20 Jan 2009 12:18:24 +0100 > Holger Macht wrote: > > > Cc: stable@kernel.org > > The patch applied OK to 2.6.28 but not to any earlier kernel. If we > decide that it should be backported to 2.6.27 or earlier, a new patch > might be needed for that. Patch that applies to stable kernel from today is attached. Thanks, Holger --=-BS20JcaEHnzBbJejXpBQ Content-Disposition: attachment; filename="acpi-dock-dont-eval-STA-on-every-show-docked-sysfs-read.patch" Content-Type: text/x-patch; name="acpi-dock-dont-eval-STA-on-every-show-docked-sysfs-read.patch"; charset="UTF-8" Content-Transfer-Encoding: 7bit Some devices trigger a DEVICE_CHECK on every evalutation of _STA. This can also be seen in commit 8b59560a3baf2e7c24e0fb92ea5d09eca92805db (acpi: dock: avoid check _STA method). If an undock is processed, the dock driver sends a uevent and userspace might read the show_docked property in sysfs. This causes an evaluation of _STA of the particular device which causes the dock driver to immediately dock again. In any case, evaluation of _STA (show_docked) does not necessarily mean that we are docked, so check with the internal device structure. http://bugzilla.kernel.org/show_bug.cgi?id=12360 Signed-off-by: Holger Macht --- diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c index 25d2161..7290e54 100644 --- a/drivers/acpi/dock.c +++ b/drivers/acpi/dock.c @@ -691,8 +691,14 @@ fdd_out: static ssize_t show_docked(struct device *dev, struct device_attribute *attr, char *buf) { - return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station)); + struct acpi_device *tmp; + + struct dock_station *dock_station = *((struct dock_station **) + dev->platform_data); + if (ACPI_SUCCESS(acpi_bus_get_device(dock_station->handle, &tmp))) + return snprintf(buf, PAGE_SIZE, "1\n"); + return snprintf(buf, PAGE_SIZE, "0\n"); } static DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL); --=-BS20JcaEHnzBbJejXpBQ--