Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756445AbYHYOaR (ORCPT ); Mon, 25 Aug 2008 10:30:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756670AbYHYO3t (ORCPT ); Mon, 25 Aug 2008 10:29:49 -0400 Received: from shadow.wildlava.net ([67.40.138.81]:58472 "EHLO shadow.wildlava.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756656AbYHYO3t (ORCPT ); Mon, 25 Aug 2008 10:29:49 -0400 Message-ID: <48B2C1DA.6070700@skyrush.com> Date: Mon, 25 Aug 2008 08:29:46 -0600 From: Joe Peterson User-Agent: Thunderbird 2.0.0.16 (X11/20080727) MIME-Version: 1.0 To: Willy Tarreau CC: Chris Frey , Vegard Nossum , linux-kernel@vger.kernel.org, Alan Cox Subject: Re: Visible Ctrl-C in latest kernels References: <20080822201537.GA18242@foursquare.net> <19f34abd0808230253w663722dcwde1303998e194ddf@mail.gmail.com> <48B04E42.3030405@skyrush.com> <20080824010231.GA26030@foursquare.net> <20080825122024.GA19337@1wt.eu> <48B2BAE7.4010702@skyrush.com> <20080825141354.GB19337@1wt.eu> In-Reply-To: <20080825141354.GB19337@1wt.eu> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1786 Lines: 36 Willy Tarreau wrote: > not mine, I was speaking about your patch of 2008/02/06 which was > talked about earlier in this thread. I was thinking that it was > possible that the signal got delayed when it was hard to print > ^C because the output was already busy spewing a stream of data. > Maybe I'm wrong, but I mean it does not cost much to try to revert > this patch when the problem is encountered. And I keep in mind > that it is possible, as you say, that your patch only makes the > problem more visible. Actually, funny you mention the case when output is busy. This actually will not cause any delay of the signal, but it instead causes the echo (not the signal) to be thrown away in the current code. If the tty driver's buffer is full, the attempted write simply returns - nothing is held. The signal is still sent right away. Now, this loss of the echo is a problem in itself, not because it delays the signals, but because the echo will not be displayed. Echo is also lost when the tty is stopped (but the signal chars restart the tty, so you will only see this for regular chars typed after, say, a ctrl-s)). I have another patch out that will fix the lost echo issue: http://marc.info/?l=linux-kernel&m=121924672730143&w=2 Note that this patch also will never cause any delay of the signals. In fact, it places the echo character in a buffer so that a full or stopped tty buffer will not cause the echoed char to be immediately discarded. The signal, same as now, is always immediately issued - no delay. -Joe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/