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From: Alan Stern <stern@rowland.harvard.edu>
To: Qais Yousef <qais.yousef@arm.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Oliver Neukum <oneukum@suse.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	USB list <linux-usb@vger.kernel.org>,
	Linux-pm mailing list <linux-pm@vger.kernel.org>,
	Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: lockdep warning in urb.c:363 usb_submit_urb
Date: Wed, 25 Mar 2020 16:49:07 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.2003251631360.1724-100000@netrider.rowland.org> (raw)
In-Reply-To: <20200325150017.xhabucfo3v6i234o@e107158-lin>

On Wed, 25 Mar 2020, Qais Yousef wrote:

> Thanks for all the hints Alan.
> 
> I think I figured it out, the below patch seems to fix it for me. Looking
> at other drivers resume functions it seems we're missing the
> pm_runtime_disable()->set_active()->enable() dance. Doing that fixes the
> warning and the dev_err() in driver/base/power.

Ah, yes.  This should have been added years ago; guess I forgot.  :-(

> I don't see xhci-plat.c doing that, I wonder if it needs it too.
> 
> I'm not well versed about the details and the rules here. So my fix could be
> a hack, though it does seem the right thing to do.
> 
> I wonder why the power core doesn't handle this transparently..

Initially, we didn't want the PM core to do this automatically because
we thought some devices might want to remain runtime-suspended
following a system resume, and only the device driver would know what 
to do.

Raphael, now that we have the direct_complete mechanism, can we revisit 
this?  Should the PM core automatically call pm_runtime_set_active() if 
dev->power.direct_complete isn't set?  Perhaps in device_resume_early() 
prior to the pm_runtime_enable() call?

It's possible we discussed this and decided against it at the time when 
direct_complete was added, but if so I don't remember what was said.

Alan Stern

> diff --git a/drivers/usb/host/ohci-platform.c b/drivers/usb/host/ohci-platform.c
> index 7addfc2cbadc..eb92c8092fae 100644
> --- a/drivers/usb/host/ohci-platform.c
> +++ b/drivers/usb/host/ohci-platform.c
> @@ -299,6 +299,10 @@ static int ohci_platform_resume(struct device *dev)
>         }
> 
>         ohci_resume(hcd, false);
> +
> +       pm_runtime_disable(dev);
> +       pm_runtime_set_active(dev);
> +       pm_runtime_enable(dev);
>         return 0;
>  }
>  #endif /* CONFIG_PM_SLEEP */
> 
> 
> Thanks
> 
> --
> Qais Yousef



       reply	other threads:[~2020-03-25 20:49 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200325150017.xhabucfo3v6i234o@e107158-lin>
2020-03-25 20:49 ` Alan Stern [this message]
2020-03-25 21:28   ` Rafael J. Wysocki
2020-03-26 12:27     ` Qais Yousef
2020-03-27 20:45       ` Alan Stern
2020-03-28 14:15         ` Rafael J. Wysocki
2020-03-28 19:58           ` Alan Stern
2020-03-29  9:16             ` Rafael J. Wysocki
2020-03-29 13:56               ` Rafael J. Wysocki
2020-03-29 16:27               ` Alan Stern
2020-04-03 15:04                 ` Rafael J. Wysocki
2020-04-03 16:13                   ` Rafael J. Wysocki
2020-04-03 16:41                   ` Alan Stern
2020-04-03 18:32                     ` Rafael J. Wysocki
2020-04-03 20:15                       ` Alan Stern
2020-04-06 16:45                         ` Rafael J. Wysocki
2020-04-06 20:25                           ` Alan Stern
2020-04-09 18:45                             ` Rafael J. Wysocki
2020-04-11  2:41                               ` Alan Stern
2020-04-13 21:32                                 ` Rafael J. Wysocki
2020-04-14 13:43                                   ` Rafael J. Wysocki
2020-04-14 17:47                                     ` Alan Stern
2020-04-15 22:20                                       ` Rafael J. Wysocki
2020-04-16 15:18                                         ` Alan Stern
2020-04-17  9:57                                           ` Rafael J. Wysocki
2020-04-17 16:10                                             ` Alan Stern
2020-04-17 21:54                                               ` Rafael J. Wysocki
2020-04-17 23:37                                                 ` Alan Stern
2020-04-18  9:40                                                   ` Rafael J. Wysocki
2020-04-03 17:08                 ` Rafael J. Wysocki
2020-04-20 20:26   ` Alan Stern
2020-04-21 11:15     ` Qais Yousef

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