Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753484AbdLNVRg (ORCPT ); Thu, 14 Dec 2017 16:17:36 -0500 Received: from imap1.codethink.co.uk ([176.9.8.82]:34271 "EHLO imap1.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752547AbdLNVRc (ORCPT ); Thu, 14 Dec 2017 16:17:32 -0500 Message-ID: <1513286249.18523.280.camel@codethink.co.uk> Subject: Re: [Y2038] [PATCH v4 1/4] uinput: Use monotonic times for uinput timestamps. From: Ben Hutchings To: Deepa Dinamani , dmitry.torokhov@gmail.com, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Cc: y2038@lists.linaro.org, peter.hutterer@who-t.net, arnd@arndb.de Date: Thu, 14 Dec 2017 21:17:29 +0000 In-Reply-To: <20171207181306.5623-2-deepa.kernel@gmail.com> References: <20171207181306.5623-1-deepa.kernel@gmail.com> <20171207181306.5623-2-deepa.kernel@gmail.com> Organization: Codethink Ltd. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1934 Lines: 51 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.) Ben. > The structure to maintain input events will be changed > in a different patch. > > Signed-off-by: Deepa Dinamani > --- >  drivers/input/misc/uinput.c | 5 ++++- >  1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c > index 39ddd9a73feb..d521aecbc078 100644 > --- a/drivers/input/misc/uinput.c > +++ b/drivers/input/misc/uinput.c > @@ -84,11 +84,14 @@ static int uinput_dev_event(struct input_dev *dev, > >       unsigned int type, unsigned int code, int value) >  { >   struct uinput_device *udev = input_get_drvdata(dev); > + struct timespec64 ts; >   >   udev->buff[udev->head].type = type; >   udev->buff[udev->head].code = code; >   udev->buff[udev->head].value = value; > - do_gettimeofday(&udev->buff[udev->head].time); > + ktime_get_ts64(&ts); > + udev->buff[udev->head].time.tv_sec = ts.tv_sec; > + udev->buff[udev->head].time.tv_usec = ts.tv_nsec / NSEC_PER_USEC; >   udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE; >   >   wake_up_interruptible(&udev->waitq); -- Ben Hutchings Software Developer, Codethink Ltd.