From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Simon Glass <sjg@chromium.org>
Cc: paulmck@linux.vnet.ibm.com, Alan Cox <alan@lxorguk.ukuu.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
"Greg Kroah-Hartman" <gregkh@suse.de>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 3/3] serial: 8250: Add a wakeup_capable module param
Date: Thu, 19 Jan 2012 01:08:32 +0100 [thread overview]
Message-ID: <201201190108.32794.rjw@sisk.pl> (raw)
In-Reply-To: <CAPnjgZ1GJatR15dVsq-+hAWhD7eaLhtN737QvBaor_=0+K+6wA@mail.gmail.com>
On Wednesday, January 18, 2012, Simon Glass wrote:
> [+cc Rafael J. Wysocki <rjw@sisk.pl> who I think wrote the wakeup.c code]
>
> Hi Alan, Paul,
>
> On Tue, Jan 17, 2012 at 8:17 PM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
> > On Tue, Jan 17, 2012 at 08:10:36PM +0000, Alan Cox wrote:
> >> On Tue, 17 Jan 2012 10:56:03 -0800
> >> Simon Glass <sjg@chromium.org> wrote:
> >>
> >> > Since serial_core now does not make serial ports wake-up capable by
> >> > default, add a parameter to support this feature in the 8250 UART.
> >> > This is the only UART where I think this feature is useful.
> >>
> >> NAK
> >>
> >> Things should just work for users. Magic parameters is not an
> >> improvement. If its a performance problem someone needs to fix the rcu
> >> sync overhead or stop using rcu on that path.
>
> OK fair enough, I agree. Every level I move down the source tree
> affects more people though.
>
> >
> > I must say that I lack context here, even after looking at the patch,
> > but the synchronize_rcu_expedited() primitives can be used if the latency
> > of synchronize_rcu() is too large.
> >
>
> Let me provide a bit of context. The serial_core code seems to be the
> only place in the kernel that does this:
>
> device_init_wakeup(tty_dev, 1);
> device_set_wakeup_enable(tty_dev, 0);
It shouldn't do that.
It should just do device_set_wakeup_capable(tty_dev, true) instead.
Thanks,
Rafael
next prev parent reply other threads:[~2012-01-19 0:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-17 18:56 [PATCH 1/3] serial: 8250: Remove trailing space in 8250 driver Simon Glass
2012-01-17 18:56 ` [PATCH 2/3] serial: Make wakeup_capable a flag to reduce boot time Simon Glass
2012-01-17 20:09 ` Alan Cox
2012-01-17 18:56 ` [PATCH 3/3] serial: 8250: Add a wakeup_capable module param Simon Glass
2012-01-17 20:10 ` Alan Cox
2012-01-18 4:17 ` Paul E. McKenney
2012-01-18 21:08 ` Simon Glass
2012-01-18 21:42 ` Paul E. McKenney
2012-01-18 22:15 ` Simon Glass
2012-01-18 22:43 ` Paul E. McKenney
2012-01-18 22:51 ` Simon Glass
2012-01-19 0:02 ` Rafael J. Wysocki
2012-01-19 1:37 ` Paul E. McKenney
2012-01-19 2:35 ` Simon Glass
2012-01-19 19:13 ` Paul E. McKenney
2012-01-20 0:03 ` Rafael J. Wysocki
2012-01-20 6:12 ` Paul E. McKenney
2012-01-20 23:49 ` Rafael J. Wysocki
2012-01-23 16:45 ` Paul E. McKenney
2012-01-23 21:04 ` Rafael J. Wysocki
2012-01-18 22:12 ` Alan Cox
2012-01-18 22:19 ` Simon Glass
2012-01-19 0:08 ` Rafael J. Wysocki [this message]
2012-01-19 0:58 ` Simon Glass
2012-01-18 23:07 ` [PATCH 1/2] power: Add function to init wakeup capability without enabling Simon Glass
2012-01-18 23:07 ` [PATCH 2/2] serial: Use device_init_wakeup_flag() to make device wakeup-capable Simon Glass
2012-01-19 0:10 ` [PATCH 1/2] power: Add function to init wakeup capability without enabling Rafael J. Wysocki
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