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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Simon Glass <sjg@chromium.org>,
	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: Tue, 17 Jan 2012 20:17:21 -0800	[thread overview]
Message-ID: <20120118041720.GA2431@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120117201036.6d99f98f@pyramind.ukuu.org.uk>

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.

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.

							Thanx, Paul


  reply	other threads:[~2012-01-18  4:17 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 [this message]
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
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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