From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Adam Jackson <ajax@redhat.com>
Cc: linux-input@vger.kernel.org
Subject: Re: [PATCH] input/evdev: Be less aggressive about sending SIGIO notifies
Date: Mon, 4 Jan 2010 22:51:53 -0800 [thread overview]
Message-ID: <20100105065153.GA28872@core.coreip.homeip.net> (raw)
In-Reply-To: <1262639297-21857-1-git-send-email-ajax@redhat.com>
On Mon, Jan 04, 2010 at 04:08:17PM -0500, Adam Jackson wrote:
> When using realtime signals, we'll enqueue one signal for every event.
> This is unfortunate, because (for example) keyboard presses are three
> events: key, msc scancode, and syn. They'll be enqueued fast enough in
> kernel space that all three events will be ready to read by the time
> userspace runs, so the first invocation of the signal handler will read
> all three events, but then the second two invocations still have to run
> to do no work.
>
> Instead, only send the SIGIO notification on syn events. This is a
> slight abuse of SIGIO semantics, in principle it ought to fire as soon
> as any events are readable. But it matches evdev semantics, which is
> more important since SIGIO is rather vaguely defined to begin with.
Makes sense, will apply. It might mess up evtest slightly (if a driver
author forgets using input_sync() ) but we have evbug for true hardcore
debugging :)
--
Dmitry
prev parent reply other threads:[~2010-01-05 6:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-04 21:08 [PATCH] input/evdev: Be less aggressive about sending SIGIO notifies Adam Jackson
2010-01-05 6:51 ` Dmitry Torokhov [this message]
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