From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: "David Härdeman" <david@hardeman.nu>
Cc: linux-input@vger.kernel.org
Subject: Re: Two questions regarding evdev
Date: Wed, 24 Mar 2010 14:41:48 -0700 [thread overview]
Message-ID: <201003241441.48437.dmitry.torokhov@gmail.com> (raw)
In-Reply-To: <20100324205332.GA7303@hardeman.nu>
Hi David,
On Wednesday 24 March 2010 01:53:32 pm David Härdeman wrote:
> I've been going over the evdev (drivers/input/evdev.c) code since I'm
> using it as inspiration for a small project I'm hacking on. So far I
> have two questions with regard to the code:
>
> First, evdev_event passes a new event to all connected clients (writing
> it to each client's event fifo) and then calls wake_up_interruptible.
> However, given that all clients will have at least one new event to read
> after evdev_event is done, shouldn't wake_up_interruptible_all be called
> instead?
wake_up() vs. wake_up_all() only matters if there is exclusive waiters
which evdev does not use. PLease see comment/explanation for wake up
here:
http://lxr.linux.no/linux+v2.6.33/kernel/sched.c#L5685
>
> Second, evdev_poll never sets the POLLOUT flag, but evdev can accept
> writes (which will be passed to input_inject_event), so shouldn't the
> POLLOUT flag always be set?
We could but I guess nobody tries to pull evdev for writing, everyone
is interested in reading.
--
Dmitry
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prev parent reply other threads:[~2010-03-24 21:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-24 20:53 Two questions regarding evdev David Härdeman
2010-03-24 21:41 ` Dmitry Torokhov [this message]
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