From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toshi Kani Subject: Re: [Update 4][PATCH 2/7] ACPI / scan: Introduce common code for ACPI-based device hotplug Date: Mon, 25 Feb 2013 11:07:52 -0700 Message-ID: <1361815672.12845.71.camel@misato.fc.hp.com> References: <3260206.bhaAobGhpZ@vostro.rjw.lan> <2482081.rPvizM7IsG@vostro.rjw.lan> <2894504.SgZF7d1Dbv@vostro.rjw.lan> <1478394.ryVNRuTre2@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from g4t0017.houston.hp.com ([15.201.24.20]:35962 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756577Ab3BYSSp (ORCPT ); Mon, 25 Feb 2013 13:18:45 -0500 In-Reply-To: <1478394.ryVNRuTre2@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: ACPI Devel Maling List , Bjorn Helgaas , LKML , Yinghai Lu , Yasuaki Ishimatsu , Jiang Liu On Sat, 2013-02-23 at 22:38 +0000, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > Multiple drivers handling hotplug-capable ACPI device nodes install > notify handlers covering the same types of events in a very similar > way. Moreover, those handlers are installed in separate namespace > walks, although that really should be done during namespace scans > carried out by acpi_bus_scan(). This leads to substantial code > duplication, unnecessary overhead and behavior that is hard to > follow. > > For this reason, introduce common code in drivers/acpi/scan.c for > handling hotplug-related notification and carrying out device > insertion and eject operations in a generic fashion, such that it > may be used by all of the relevant drivers in the future. To cover > the existing differences between those drivers introduce struct > acpi_hotplug_profile for representing collections of hotplug > settings associated with different ACPI scan handlers that can be > used by the drivers to make the common code reflect their current > behavior. > > Signed-off-by: Rafael J. Wysocki > --- > > This update causes acpi_bus_device_eject() to only emit KOBJ_OFFLINE uevent if > autoexec is unset for the given scan handler. > > This will require the doc in patch [5/7] to be updated which I'm going to do if > everyone is OK with the $subject patch. > > Thanks, > Rafael : > + > +static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source) > +{ > + struct acpi_device *device = NULL; > + u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; > + int error; > + > + mutex_lock(&acpi_scan_lock); > + > + acpi_bus_get_device(handle, &device); > + if (device) { > + dev_warn(&device->dev, "Attempt to re-insert\n"); > + goto out; > + } > + acpi_evaluate_hotplug_ost(handle, ost_source, > + ACPI_OST_SC_INSERT_IN_PROGRESS, NULL); > + error = acpi_bus_scan(handle); > + if (error) { > + acpi_handle_warn(handle, "Namespace scan failure\n"); > + goto out; > + } > + error = acpi_bus_get_device(handle, &device); > + if (error) { > + acpi_handle_warn(handle, "Missing device node object\n"); > + goto out; > + } > + ost_code = ACPI_OST_SC_SUCCESS; > + if (device->handler && device->handler->hotplug.uevents) > + kobject_uevent(&device->dev.kobj, KOBJ_ONLINE); I confirmed that the uevent crash issue was solved. Thinking further, I wonder if we need to emit KOBJ_ONLINE here. This behavior is asymmetric since we do not emit KOBJ_OFFLINE when autoeject is set. The definition of ONLINE/OFFLINE event to an ACPI device object seems also bogus since there is no online/offline operation to the ACPI device object itself. Online/offline operation is only possible to actual device, such as system/cpu/cpu% and system/memory/memory%. So, I'd suggest the following changes. - Remove the "uevents" attribute. KOBJ_ONLINE/OFFLINE are not used for ACPI device objects. - Make the !autoeject case as an exception for now, and emit KOBJ_OFFLINE as a way to request off-lining to user. This uevent is tied with the !autoeject case. We can then revisit if this use-case needs to be supported going forward. If so, we may want to consider a different event type. Thanks, -Toshi