Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753823AbdLNVok (ORCPT ); Thu, 14 Dec 2017 16:44:40 -0500 Received: from mail-it0-f66.google.com ([209.85.214.66]:44060 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbdLNVoh (ORCPT ); Thu, 14 Dec 2017 16:44:37 -0500 X-Google-Smtp-Source: ACJfBotLBWb/y3tHEWirqTM349NMKofg/ppogCitQdVz9FQJHbfBBE07L5ydpzN/5c4oPcvhYs7NOrxEErjd8QrNal4= MIME-Version: 1.0 In-Reply-To: <1513286332.18523.281.camel@codethink.co.uk> References: <20171207181306.5623-1-deepa.kernel@gmail.com> <20171207181306.5623-2-deepa.kernel@gmail.com> <1513286249.18523.280.camel@codethink.co.uk> <1513286332.18523.281.camel@codethink.co.uk> From: Deepa Dinamani Date: Thu, 14 Dec 2017 13:44:35 -0800 Message-ID: Subject: Re: [Y2038] [PATCH v4 1/4] uinput: Use monotonic times for uinput timestamps. To: Ben Hutchings Cc: Dmitry Torokhov , "open list:HID CORE LAYER" , Linux Kernel Mailing List , y2038 Mailman List , Peter Hutterer , Arnd Bergmann Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1335 Lines: 31 On Thu, Dec 14, 2017 at 1:18 PM, Ben Hutchings wrote: > On Thu, 2017-12-14 at 21:17 +0000, Ben Hutchings wrote: >> On Thu, 2017-12-07 at 10:13 -0800, Deepa Dinamani wrote: >> > struct timeval which is part of struct input_event to >> > maintain the event times is not y2038 safe. >> > >> > Real time timestamps are also not ideal for input_event >> > as this time can go backwards as noted in the patch >> > a80b83b7b8 by John Stultz. >> > >> > The patch switches the timestamps to use monotonic time >> > from realtime time. This is assuming no one is using >> > absolute times from these timestamps. >> >> Why is this change not opt-in, as for evdev? I assume there were >> compatibility reasons for not changing evdev's clock by default, so I >> would expect them to apply to uinput as well. (But I'm also prepared >> to believe that user-space is now generally compatible with and would >> prefer monotonic time from all input devices.) > > Never mind, I've gone back and seen Arnd's comments about compatibility > on v3. It might be worth copying those into the commit message though. Commit message already talks about this assumption?: The patch switches the timestamps to use monotonic time from realtime time. This is assuming no one is using absolute times from these timestamps. -Deepa