From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Qais Yousef <qais.yousef@arm.com>,
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: Sun, 29 Mar 2020 15:56:32 +0200 [thread overview]
Message-ID: <CAJZ5v0horQNK4EBnNyFAz1gCe=SKJ_f9-5yiMeP=Scq31gscQg@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0igUZnqFLcOhruDSNjv0HqCsy64tmYWyTX98xEc9cH14g@mail.gmail.com>
On Sun, Mar 29, 2020 at 11:16 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
[cut]
> >
> > But if SMART_SUSPEND is set and the device is runtime-suspended, why
> > issue the ->suspend callback?
>
> The driver itself or the middle-layer may want to resume the device.
>
> Arguably, it may do that in ->prepare() too,
Not really.
The problem is that that device_prepare() is executed synchronously
for all devices, so if multiple devices needed to be resumed, the
latency would accumulate if that happened in device_prepare().
Cheers!
next prev parent reply other threads:[~2020-03-29 13:56 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 ` lockdep warning in urb.c:363 usb_submit_urb Alan Stern
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 [this message]
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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