linux-kernel - Re: [Update][PATCH 3/3] ACPI / dock / PCI: Synchronous handling of dock events for PCI devices

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Date:	Sun, 23 Jun 2013 16:04:52 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	Jiang Liu <liuj97@...il.com>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"Alexander E . Patrakov" <patrakov@...il.com>,
	Jiang Liu <jiang.liu@...wei.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Yijing Wang <wangyijing@...wei.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [Update][PATCH 3/3] ACPI / dock / PCI: Synchronous handling of
 dock events for PCI devices

On Sun, Jun 23, 2013 at 2:42 PM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> On Sunday, June 23, 2013 01:29:19 PM Yinghai Lu wrote:
>> On Sun, Jun 23, 2013 at 12:57 PM, Yinghai Lu <yinghai@...nel.org> wrote:
>> > On Sun, Jun 23, 2013 at 8:54 AM, Jiang Liu <liuj97@...il.com> wrote:
>> >> On 06/23/2013 05:25 AM, Rafael J. Wysocki wrote:
>> >>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> >>>
>> >>> The interactions between the ACPI dock driver and the ACPI-based PCI
>> >>> hotplug (acpiphp) are currently problematic because of ordering
>> >>> issues during hot-remove operations.
>> >>>
>> >>> First of all, the current ACPI glue code expects that physical
>> >>> devices will always be deleted before deleting the companion ACPI
>> >>> device objects.  Otherwise, acpi_unbind_one() will fail with a
>> >>> warning message printed to the kernel log, for example:
>> >>>
>> >>> [  185.026073] usb usb5: Oops, 'acpi_handle' corrupt
>> >>> [  185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
>> >>> [  185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
>> >>> [  180.013656]  port1: Oops, 'acpi_handle' corrupt
>> >>>
>> >> [...]
>> >>> @@ -597,15 +654,11 @@ register_hotplug_dock_device(acpi_handle
>> >>>                * ops
>> >>>                */
>> >>>               dd = find_dock_dependent_device(dock_station, handle);
>> >>> -             if (dd) {
>> >>> -                     dd->ops = ops;
>> >>> -                     dd->context = context;
>> >>> -                     dock_add_hotplug_device(dock_station, dd);
>> >>> -                     ret = 0;
>> >>> -             }
>> >>> +             if (dd)
>> >>> +                     return dock_init_hotplug(dd, ops, context,
>> >>> +                                              init, release);
>> >> Hi Rafael,
>> >>         Seems not an equivalent change. According to the comment just above the
>> >> code, we shouldn't return but continue here.
>> >> /*
>> >>  * An ATA bay can be in a dock and itself can be ejected
>> >>  * separately, so there are two 'dock stations' which need the
>> >>  * ops
>> >>  */
>> >
>> > two dock stations:
>> > Do you mean two dock station has same handle?
>> >
>> > dock_add should add correctly flags for IS_DOCK and IS_ATA.
>> > if one handle has _DCK and _GTF etc.
>> >
>> > or do you mean there are two dependent devices with same handle?
>> > like one is for acpiphp slot and one is for ATA?
>>
>> related commit:
>> commit 61b836958371c717d1e6d4fea1d2c512969ad20b
>> Author: Shaohua Li <shaohua.li@...el.com>
>> Date:   Thu Aug 28 10:07:14 2008 +0800
>>
>>     dock: fix for ATA bay in a dock station
>>
>>     an ATA bay can be in a dock and itself can be ejected separately.
>>     This patch handles such eject bay. Found by Holger.
>>
>>     Signed-off-by: Shaohua Li <shaohua.li@...el.com>
>>     Signed-off-by: Len Brown <len.brown@...el.com>
>> @@ -618,16 +619,21 @@ register_hotplug_dock_device(acpi_handle handle, struct ac
>> pi_dock_ops *ops,
>>          * this would include the dock station itself
>>          */
>>         list_for_each_entry(dock_station, &dock_stations, sibiling) {
>> +               /*
>> +                * An ATA bay can be in a dock and itself can be ejected
>> +                * seperately, so there are two 'dock stations' which need the
>> +                * ops
>> +                */
>>                 dd = find_dock_dependent_device(dock_station, handle);
>>                 if (dd) {
>>                         dd->ops = ops;
>>                         dd->context = context;
>>                         dock_add_hotplug_device(dock_station, dd);
>> -                       return 0;
>> +                       ret = 0;
>>                 }
>>         }
>>
>> -       return -EINVAL;
>> +       return ret;
>>  }
>>
>> so two doc station with different handle.
>>
>> and dependent devices in both...
>>
>> looks like Rafael's change can not handle this case anymore.
>
> Ah, I overlooked the fact that each dock station is on its own dependent_list
> and can also be on another dock station's dependent_list.  I'm not sure if that
> makes sense, but let's not break the backwards compatibility here.

wonder if dock_release_hotplug with second dock_station and dd will
have problem.

as first one dock_station/dd, could have hp_context release already,
then second one could all release(context) again....

so looks like dock_release_hotplug should go over dock_station/dd list
to clear hp_context in other dock_station/... if they are the same?

Yinghai
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