From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Simon Glass <sjg@chromium.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@suse.de>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH 2/3] serial: Make wakeup_capable a flag to reduce boot time
Date: Tue, 17 Jan 2012 20:09:42 +0000 [thread overview]
Message-ID: <20120117200942.7e7adf09@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <1326826563-32215-2-git-send-email-sjg@chromium.org>
On Tue, 17 Jan 2012 10:56:02 -0800
Simon Glass <sjg@chromium.org> wrote:
> The synchronize_rcu() call resulting from making every serial driver
> wake-up capable (commit b3b708fa) slows boot down by 600ms on my Tegra2x
> system (with CONFIG_PREEMPT disabled).
>
> Waking up the machine from a serial port seems to be an unlikely
> requirement, so make serial_core default to not using the behaviour.
Its quite normal on x86, and very very common on embedded. Sorry someone
needs to fix the root cause not hack the driver.
The other question would be whether in PC space you can deduce the wake
up situation from ACPI data ? One for Len ?
Alan
next prev parent reply other threads:[~2012-01-17 20:08 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 [this message]
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
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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