From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yasuaki Ishimatsu Subject: Re: [Update 4][PATCH 2/7] ACPI / scan: Introduce common code for ACPI-based device hotplug Date: Tue, 26 Feb 2013 11:02:56 +0900 Message-ID: <512C17D0.8080102@jp.fujitsu.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> <1361840942.12845.84.camel@misato.fc.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:47989 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758612Ab3BZCDY (ORCPT ); Mon, 25 Feb 2013 21:03:24 -0500 In-Reply-To: <1361840942.12845.84.camel@misato.fc.hp.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Toshi Kani Cc: "Rafael J. Wysocki" , ACPI Devel Maling List , Bjorn Helgaas , LKML , Yinghai Lu , Jiang Liu 2013/02/26 10:09, Toshi Kani wrote: > 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? My application does not distinguish between ADD and ONLINE events currently. But if the event is changed from ONLINE to ADD, I will change my application. Thanks, Yasuaki Ishimatsu > > -Toshi > >