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[72.182.52.210]) by smtp.googlemail.com with ESMTPSA id k135sm25007479oih.1.2019.08.01.05.42.01 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 01 Aug 2019 05:42:01 -0700 (PDT) Subject: Re: [PATCH v2 7/7] n_tty: Provide an informational line on VSTATUS receipt To: Greg Kroah-Hartman , Arseny Maslennikov Cc: Jiri Slaby , Ingo Molnar , Peter Zijlstra , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, "Vladimir D. Seleznev" , "Eric W. Biederman" , Pavel Machek References: <20190625161153.29811-1-ar@cs.msu.ru> <20190625161153.29811-8-ar@cs.msu.ru> <20190730161940.GA15798@kroah.com> <20190731222359.GA20574@cello> <20190801092020.GB19329@kroah.com> From: Rob Landley Message-ID: Date: Thu, 1 Aug 2019 07:44:30 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190801092020.GB19329@kroah.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/1/19 4:20 AM, Greg Kroah-Hartman wrote: >> SysRq is system-wide, whereas this is per-terminal and only cares about >> one tty which the status char is pressed at and its foreground pgrp >> (most likely it's the foreground shell job). >> >> I hope this is clear enough. > > It is, yes. My big objection is the crazy code I point out above, as > well as the "create a totally new interface when we might be able to use > an existing one" that you need to convince me is really required :) It's not a new interface, it's a multiple decades old BSD interface our tcgetattr man page already mentions, which seems to be one of the big things BSD people miss when using Linux, and which I tried and failed to implement without kernel support months ago. I wasn't involved in this kernel patch effort, I got pointed at news coverage about it by the Android Bionic maintainer: http://lists.landley.net/pipermail/toybox-landley.net/2019-June/010536.html Which is how I wound up cc'd on this thread. I don't think Android specifically cares about SIGINFO, but they're trying to support building Android on MacOSX, which means trying to support building it on FreeBSD, which involves outreach to the BSD community, and they brought up the lack of ctrl-T and siginfo as a thing they really missed when having to deal with the Linux command line. (The fact there _was_ news coverage of the patch for somebody to point me at may also be an indication of interest floating around out there...) Rob