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 18:09:02 -0700 Message-ID: <1361840942.12845.84.camel@misato.fc.hp.com> References: <3260206.bhaAobGhpZ@vostro.rjw.lan> <1478394.ryVNRuTre2@vostro.rjw.lan> <1361815672.12845.71.camel@misato.fc.hp.com> <18666371.hyHAvqrdQ6@vostro.rjw.lan> <512C046E.8050501@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from g5t0009.atlanta.hp.com ([15.192.0.46]:34468 "EHLO g5t0009.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758168Ab3BZBT4 (ORCPT ); Mon, 25 Feb 2013 20:19:56 -0500 In-Reply-To: <512C046E.8050501@jp.fujitsu.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Yasuaki Ishimatsu Cc: "Rafael J. Wysocki" , ACPI Devel Maling List , Bjorn Helgaas , LKML , Yinghai Lu , Jiang Liu On Tue, 2013-02-26 at 09:40 +0900, Yasuaki Ishimatsu wrote: > 2013/02/26 8:39, Rafael J. Wysocki wrote: > > On Monday, February 25, 2013 11:07:52 AM Toshi Kani wrote: > >> 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. > > > > Well, I put that in there only to be able to make the container driver behave > > in a backwards compatible way (which is to emit KOBJ_ONLINE at this point). > > > > If the container driver doesn't need to emit KOBJ_ONLINE at all, I agree with > > your suggestion. > > > >> 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%. > > > > That's correct, but I don't know what the user space expectations are > > currently. > > My system expects this event to be notified when hot adding container device. > My container device has cpu and memory. As Toshi said, these devices are > offline when hot adding container device. So in my system, when notifying > container device's KOBJ_ONLINE event, my application runs for onlining these > devices. If this event is not notified to user land, we cannot online these > devices automatically. Thanks for the info. Can your application listen KOBJ_ADD to a container device, instead of KOBJ_ONLINE? IOW, does it distinguish between ADD and ONLINE events to a container device? -Toshi