linux-kernel - Re: [PATCH v12 2/4] PM / Domains: add setter for dev.pm

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Message-ID: <CAHp75Vf9TS-AxJALQjiwNjMCT8ct5SBanYzrEsV9aj=DsUw-OA@mail.gmail.com>
Date:	Fri, 29 Jan 2016 18:35:49 +0200
From:	Andy Shevchenko <andy.shevchenko@...il.com>
To:	Tomeu Vizoso <tomeu.vizoso@...labora.com>
Cc:	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	martyn.welch@...labora.co.uk, Ulf Hansson <ulf.hansson@...aro.org>,
	Daniel Kurtz <djkurtz@...omium.org>,
	David Airlie <airlied@...ux.ie>,
	Tomas Winkler <tomas.winkler@...el.com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	dri-devel@...ts.freedesktop.org,
	Russell King <linux@....linux.org.uk>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kevin Hilman <khilman@...nel.org>,
	Tony Lindgren <tony@...mide.com>, Len Brown <lenb@...nel.org>,
	Linux OMAP Mailing List <linux-omap@...r.kernel.org>,
	Pavel Machek <pavel@....cz>,
	linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v12 2/4] PM / Domains: add setter for dev.pm_domain

On Fri, Jan 29, 2016 at 5:51 PM, Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Fri, Jan 29, 2016 at 5:38 PM, Andy Shevchenko
> <andy.shevchenko@...il.com> wrote:
>> On Thu, Jan 7, 2016 at 5:46 PM, Tomeu Vizoso <tomeu.vizoso@...labora.com> wrote:
>>> Adds a function that sets the pointer to dev_pm_domain in struct device
>>> and that warns if the device has already finished probing. The reason
>>> why we want to enforce that is because in the general case that can
>>> cause problems and also that we can simplify code quite a bit if we can
>>> always assume that.
>>>
>>> This patch also changes all current code that directly sets the
>>> dev.pm_domain pointer.
>>
>>
>>> --- a/drivers/acpi/acpi_lpss.c
>>> +++ b/drivers/acpi/acpi_lpss.c
>>
>>> @@ -875,13 +876,14 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
>>>
>>>         switch (action) {
>>>         case BUS_NOTIFY_BIND_DRIVER:
>>> -               pdev->dev.pm_domain = &acpi_lpss_pm_domain;
>>> +               dev_pm_domain_set(&pdev->dev, &acpi_lpss_pm_domain);
>>>                 break;
>>>         case BUS_NOTIFY_DRIVER_NOT_BOUND:
>>>         case BUS_NOTIFY_UNBOUND_DRIVER:
>>>                 pdev->dev.pm_domain = NULL;
>>
>> Missed?
>>
>>>                 break;
>>>         case BUS_NOTIFY_ADD_DEVICE:
>>> +               dev_pm_domain_set(&pdev->dev, &acpi_lpss_pm_domain);
>>>                 if (pdata->dev_desc->flags & LPSS_LTR)
>>>                         return sysfs_create_group(&pdev->dev.kobj,
>>>                                                   &lpss_attr_group);
>>> @@ -889,6 +891,7 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb,
>>>         case BUS_NOTIFY_DEL_DEVICE:
>>>                 if (pdata->dev_desc->flags & LPSS_LTR)
>>>                         sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
>>> +               dev_pm_domain_set(&pdev->dev, NULL);
>>>                 break;
>>>         default:
>>>                 break;
>>
>> This looks wrong. I didn't test yet, but I have concerns here. Why did
>> you add those calls?
>
>
> Okay, for first glance it seems working on Intel Braswell.

One more test unveils this one

# modprobe -r sdhci-acpi
[ 1289.909441] ------------[ cut here ]------------
[ 1289.918205] WARNING: CPU: 1 PID: 4374 at
/home/andy/prj/linux-otc/drivers/base/power/common.c:150
dev_pm_domain_set+0x51/0x60()
[ 1289.934681] PM domains can only be changed for unbound devices
[ 1289.944843] Modules linked in: sdhci_acpi(-) sdhci mmc_core
led_class [last unloaded: dw_dmac_core]
[ 1289.958802] CPU: 1 PID: 4374 Comm: modprobe Not tainted 4.5.0-rc1+ #3
[ 1289.969736]  ffffffff81c38330 ffff88007bb53d18 ffffffff8133162f
ffff88007bb53d60
[ 1289.981844]  ffff88007bb53d50 ffffffff8105cd12 ffff88017a007410
0000000000000000
[ 1289.993996]  0000000000000001 0000000000000080 0000000000000000
ffff88007bb53db0
[ 1290.006123] Call Trace:
[ 1290.012600]  [<ffffffff8133162f>] dump_stack+0x44/0x55
[ 1290.022052]  [<ffffffff8105cd12>] warn_slowpath_common+0x82/0xc0
[ 1290.032462]  [<ffffffff8105cd9c>] warn_slowpath_fmt+0x4c/0x50
[ 1290.042589]  [<ffffffff814867c1>] dev_pm_domain_set+0x51/0x60
[ 1290.052695]  [<ffffffff813a62a9>] acpi_dev_pm_detach+0x3f/0x84
[ 1290.062910]  [<ffffffff81486747>] dev_pm_domain_detach+0x27/0x30
[ 1290.073294]  [<ffffffff81480188>] platform_drv_remove+0x38/0x40
[ 1290.083585]  [<ffffffff8147da51>] __device_release_driver+0xa1/0x160
[ 1290.094335]  [<ffffffff8147e5a6>] driver_detach+0xa6/0xb0
[ 1290.104009]  [<ffffffff8147d435>] bus_remove_driver+0x55/0xd0
[ 1290.114053]  [<ffffffff8147eccc>] driver_unregister+0x2c/0x50
[ 1290.124076]  [<ffffffff81480232>] platform_driver_unregister+0x12/0x20
[ 1290.134957]  [<ffffffffa003681c>] sdhci_acpi_driver_exit+0x10/0x12
[sdhci_acpi]
[ 1290.146730]  [<ffffffff810ce0e9>] SyS_delete_module+0x199/0x240
[ 1290.156907]  [<ffffffff8100219b>] ? exit_to_usermode_loop+0x8b/0x90
[ 1290.167478]  [<ffffffff81002b83>] do_syscall_32_irqs_off+0x53/0xa0
[ 1290.177949]  [<ffffffff818b7f9a>] entry_INT80_compat+0x2a/0x40
[ 1290.187986] ---[ end trace a8351c0506ee239b ]---
[ 1290.213855] mmc0: card 0001 removed

Which function is guilty?

> But can
> yoyu point me out what was going on before this patch?

-- 
With Best Regards,
Andy Shevchenko