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Message-ID: <6782022.RtGDcVFnWK@vostro.rjw.lan>
Date: Fri, 31 Jan 2014 18:34:22 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Aaron Lu <aaron.lu@...el.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linux PCI <linux-pci@...r.kernel.org>
Subject: Re: [Update][PATCH 4/5][RFT] ACPI / hotplug / PCI: Simplify acpi_install_hotplug_notify_handler()
On Friday, January 31, 2014 07:09:51 PM Mika Westerberg wrote:
> On Fri, Jan 31, 2014 at 05:16:03PM +0100, Rafael J. Wysocki wrote:
> > On Friday, January 31, 2014 06:01:57 PM Mika Westerberg wrote:
> > > On Fri, Jan 31, 2014 at 05:40:11PM +0200, Mika Westerberg wrote:
> > > > On Fri, Jan 31, 2014 at 04:42:21PM +0100, Rafael J. Wysocki wrote:
> > > > > On Friday, January 31, 2014 05:28:36 PM Mika Westerberg wrote:
> > > > > > On Wed, Jan 29, 2014 at 01:00:57AM +0100, Rafael J. Wysocki wrote:
> > > > > > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > > > > >
> > > > > > > Use the observation that the ACPI scan handler of the device object
> > > > > > > in acpi_hotplug_notify_cb() can be obtained from that device object's
> > > > > > > handler pointer and do not pass it as data to
> > > > > > > acpi_install_hotplug_notify_handler() in acpi_scan_init_hotplug().
> > > > > > >
> > > > > > > That allows the second argument of acpi_install_hotplug_notify_handler()
> > > > > > > to be dropped, so do it and update its callers accordingly.
> > > > > > >
> > > > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > > > > > ---
> > > > > > > drivers/acpi/scan.c | 31 ++++++++++++++++++-------------
> > > > > > > drivers/pci/hotplug/acpiphp_glue.c | 2 +-
> > > > > > > include/acpi/acpi_bus.h | 2 +-
> > > > > > > 3 files changed, 20 insertions(+), 15 deletions(-)
> > > > > > >
> > > > > > > Index: linux-pm/drivers/acpi/scan.c
> > > > > > > ===================================================================
> > > > > > > --- linux-pm.orig/drivers/acpi/scan.c
> > > > > > > +++ linux-pm/drivers/acpi/scan.c
> > > > > > > @@ -487,7 +487,6 @@ static void acpi_device_hotplug(void *da
> > > > > > >
> > > > > > > static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
> > > > > > > {
> > > > > > > - struct acpi_scan_handler *handler = data;
> > > > > > > u32 ost_code = ACPI_OST_SC_SUCCESS;
> > > > > > > struct acpi_device *adev;
> > > > > > > acpi_status status;
> > > > > > > @@ -503,13 +502,6 @@ static void acpi_hotplug_notify_cb(acpi_
> > > > > > >
> > > > > > > case ACPI_NOTIFY_EJECT_REQUEST:
> > > > > > > acpi_handle_debug(handle, "ACPI_NOTIFY_EJECT_REQUEST event\n");
> > > > > > > - if (handler && !handler->hotplug.enabled) {
> > > > > > > - acpi_handle_err(handle, "Eject disabled\n");
> > > > > > > - ost_code = ACPI_OST_SC_EJECT_NOT_SUPPORTED;
> > > > > > > - goto out;
> > > > > > > - }
> > > > > > > - acpi_evaluate_hotplug_ost(handle, ACPI_NOTIFY_EJECT_REQUEST,
> > > > > > > - ACPI_OST_SC_EJECT_IN_PROGRESS, NULL);
> > > > > > > break;
> > > > > > >
> > > > > > > case ACPI_NOTIFY_DEVICE_WAKE:
> > > > > > > @@ -535,11 +527,24 @@ static void acpi_hotplug_notify_cb(acpi_
> > > > > > > goto out;
> > > > > > > }
> > > > > > >
> > > > > > > + mutex_lock(&acpi_scan_lock);
> > > > > >
> > > > > > This is weird. I'm testing against your test-next branch which has this
> > > > > > patch included. If I remove locking here, TBT hotplug works fine. Otherwise
> > > > > > I can see the first hotplug/unplug works but after that I cannot get any
> > > > > > events anymore.
> > > > >
> > > > > Weird indeed. I don't seem to be able to reproduce that on my Aspire S5.
> > > > >
> > > > > What system are you testing on?
> > > >
> > > > This is Intel NUC. Let me see if I can reproduce this on S5 with longer
> > > > chain of devices.
> > >
> > > OK, so on S5 this works even with longer chain. However, exactly the same
> > > kernel image on NUC fails after first hotplug/unplug cycle.
> >
> > Well, we need to figure out what happens there.
> >
> > Please add printks (1) before mutex_lock(), (2) before the if (type == ...)
> > instruction, (3) before the acpi_evaluate_hotplug_ost() under the if () and (4)
> > before the get_device() in acpi_notify_hotplug_cb() and check if they are all
> > printed (on NUC).
>
> Looks like something doesn't release that lock. I added printks what you
> suggested and after first hotplug/unplug last messages I get are:
>
> [ 64.914639] ACPI: \_SB_.PCI0.RP05: ACPI_NOTIFY_BUS_CHECK event
> [ 64.914640] ACPI: \_SB_.PCI0.RP05: BEFORE mutex_lock()
>
> Then running sysrq-w I get following task as blocked:
>
> [ 346.885950] SysRq : Show Blocked State
> [ 346.887733] task PC stack pid father
> [ 346.889535] kworker/0:0 D ffff880100241ae0 5280 4 2 0x00000000
> [ 346.891355] Workqueue: kacpi_notify acpi_os_execute_deferred
> [ 346.893171] ffff8801003c7d30 0000000000000046 ffff880100241710 ffffffff81e10460
> [ 346.895011] ffff8801003c7fd8 00000000000129c0 00000000000129c0 ffff880100241710
> [ 346.896849] ffffffff81e5db70 ffffffff81e5db74 ffff880100241710 00000000ffffffff
> [ 346.898702] Call Trace:
> [ 346.900518] [<ffffffff81815bc4>] schedule_preempt_disabled+0x24/0x70
> [ 346.902338] [<ffffffff818175f2>] __mutex_lock_slowpath+0x132/0x1b0
> [ 346.904164] [<ffffffff8181768a>] mutex_lock+0x1a/0x2a
> [ 346.905993] [<ffffffff81324845>] acpi_hotplug_notify_cb+0x70/0x227
> [ 346.907820] [<ffffffff813384f4>] acpi_ev_notify_dispatch+0x44/0x5c
> [ 346.909637] [<ffffffff8131fa8d>] acpi_os_execute_deferred+0xf/0x1b
> [ 346.911455] [<ffffffff8105e12a>] process_one_work+0x17a/0x440
> [ 346.913285] [<ffffffff8105ed29>] worker_thread+0x119/0x390
> [ 346.915121] [<ffffffff8105ec10>] ? manage_workers.isra.25+0x2a0/0x2a0
> [ 346.916970] [<ffffffff81064dad>] kthread+0xcd/0xf0
> [ 346.918809] [<ffffffff81064ce0>] ? kthread_create_on_node+0x180/0x180
> [ 346.920653] [<ffffffff8181fefc>] ret_from_fork+0x7c/0xb0
> [ 346.922501] [<ffffffff81064ce0>] ? kthread_create_on_node+0x180/0x180
> [ 346.924351] kworker/u8:5 D ffff88006ea55860 4696 945 2 0x00000000
> [ 346.926212] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
> [ 346.928074] ffff88006de49a40 0000000000000046 ffff88006ea55490 ffff880100245490
> [ 346.929978] ffff88006de49fd8 00000000000129c0 00000000000129c0 ffff88006ea55490
> [ 346.931872] ffff88006de49ba0 7fffffffffffffff ffff88006de49b98 ffff88006ea55490
> [ 346.933753] Call Trace:
> [ 346.935626] [<ffffffff81815794>] schedule+0x24/0x70
> [ 346.937516] [<ffffffff81814a89>] schedule_timeout+0x1a9/0x2a0
> [ 346.939415] [<ffffffff8107dda8>] ? __wake_up_common+0x58/0x90
> [ 346.941312] [<ffffffff81816968>] wait_for_completion+0x98/0x100
> [ 346.943222] [<ffffffff81071b70>] ? wake_up_state+0x10/0x10
> [ 346.945133] [<ffffffff8105ba25>] flush_workqueue+0x115/0x5a0
> [ 346.947054] [<ffffffff81309b20>] ? acpi_pci_find_companion+0x40/0x40
> [ 346.948986] [<ffffffff81309b20>] ? acpi_pci_find_companion+0x40/0x40
> [ 346.950904] [<ffffffff81320340>] acpi_os_wait_events_complete+0x1c/0x1e
> [ 346.952829] [<ffffffff8133a387>] acpi_remove_notify_handler+0x78/0x1ef
> [ 346.954748] [<ffffffff81309b20>] ? acpi_pci_find_companion+0x40/0x40
> [ 346.956669] [<ffffffff813226df>] acpi_remove_pm_notifier+0x39/0x5c
> [ 346.958592] [<ffffffff81309ab5>] pci_acpi_cleanup+0x25/0x50
> [ 346.960508] [<ffffffff8132368c>] acpi_platform_notify_remove+0x44/0x53
> [ 346.962427] [<ffffffff814426f2>] device_del+0x142/0x1b0
> [ 346.964333] [<ffffffff812edcfa>] pci_remove_bus_device+0x7a/0x100
> [ 346.966238] [<ffffffff812edd95>] pci_stop_and_remove_bus_device+0x15/0x20
> [ 346.968140] [<ffffffff8130639e>] disable_slot+0x4e/0xa0
> [ 346.970030] [<ffffffff813067b8>] acpiphp_check_bridge.part.10+0xe8/0xf0
> [ 346.971911] [<ffffffff81306f92>] hotplug_event+0xf2/0x1a0
> [ 346.973776] [<ffffffff813070a1>] acpiphp_hotplug_event+0x61/0xe0
> [ 346.975630] [<ffffffff8132634e>] acpi_device_hotplug+0x37c/0x3c2
> [ 346.977471] [<ffffffff81320359>] acpi_hotplug_work_fn+0x17/0x22
> [ 346.979299] [<ffffffff8105e12a>] process_one_work+0x17a/0x440
> [ 346.981122] [<ffffffff8105ed29>] worker_thread+0x119/0x390
> [ 346.982956] [<ffffffff8105ec10>] ? manage_workers.isra.25+0x2a0/0x2a0
> [ 346.984762] [<ffffffff81064dad>] kthread+0xcd/0xf0
> [ 346.986581] [<ffffffff81064ce0>] ? kthread_create_on_node+0x180/0x180
> [ 346.988419] [<ffffffff8181fefc>] ret_from_fork+0x7c/0xb0
> [ 346.990221] [<ffffffff81064ce0>] ? kthread_create_on_node+0x180/0x180
>
> I have to leave now but I can continue debugging tomorrow if needed.
No need for now, I think I know what's happening. I'll follow up later.
Thanks!
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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