From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752499AbbIOOCP (ORCPT ); Tue, 15 Sep 2015 10:02:15 -0400 Received: from mout.kundenserver.de ([212.227.17.13]:60510 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752286AbbIOOCK (ORCPT ); Tue, 15 Sep 2015 10:02:10 -0400 From: Arnd Bergmann To: Pingbo Wen Cc: y2038@lists.linaro.org, linux-usb@vger.kernel.org, Felipe Balbi , linux-kernel@vger.kernel.org Subject: Re: [Y2038] [PATCH] dummy_hcd: replace timeval with timespec64 Date: Tue, 15 Sep 2015 16:02:07 +0200 Message-ID: <2172732.1i8HcJyCZj@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <55F82077.5050603@linaro.org> References: <1442321775-32324-1-git-send-email-pingbo.wen@linaro.org> <1446144.x46ug1hXZL@wuerfel> <55F82077.5050603@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:o+lL9ypLKKAB3m7m8RDmOqydyp7lYusMI1fDTb5pMZwXFEDUsZ4 rn1GnGVkaLZX/sIFzqClqluw+xlNxwkC0bsIlquNbimevv4see/r4aXF7w0xs6V2Rimj7O3 rzXUQ0F8amXXAflO9Kgh3hk7BXwqtT5JIg1paQ6D9GAmmZ8IZj1IjsuKBmMgLAsQqcHQgv9 e0AIaZVdB6mv9KBEkvaBw== X-UI-Out-Filterresults: notjunk:1;V01:K0:JehxNYoY2Hs=:4hN86rMEqdRAzHNTwqahgX Kz/Su/Pf2RkXLYB3m8b3+K07bi+tQ02OOGSGd97W5tEun5uAUDDbtOFtIIhg8MtsbaP3D6Bto rMZiIIZnPWdNW5Kw7v5KG1Jbjciz6toHujTzbPzX+nE9x0gYldEncvQkYqbpz3cdGOAV0Y/tD Xe2ss0/kDHw4xNri2MR9BokdugiWykm/O/MV2xjwlfypHBnOymKb2NfKr9uv2OABYuq3AKUe3 +W4F1j+dQmwFsQHGN5iXhZPiKcCVIdE2AIpMpmpoE+c56FARsBFkZsbECAnd6BlFKuSG5NMgp 1LPBmHjiZrxdRBilfyhb176aQDY8CGOjHCImkR4ODA2H1R5PH0Ip9OgE1iCUR+m7TANcVxwAe 1H7m82Cf7cMhUQa7XGwqPnzOeT90AbW0ZvEw/FuRQH5tfp6xsbDWkWJAzLYIKEcW/B2tsYWKz aAdF9tp/pPHfG1sMnsfIwcfwXqLePrbYxObdeoFsw8kH5GUhVbexjRiCa3WokgMVhYCfEOcaj 4TZyfokzKnaJvjzKPCMfMy6x7qxe4rSs9l6CuCMmVSpVkggy99wVATxSI+g3g4n2/U1TWhteZ cwMkD1Xzb17ZCRm73NzZh8JAY7R4ih6g6u8BaUs2T/sHJiwLeBHQrQ7GSJ37fjGfhdwXo5bUW 9w1J0eUpTmfJa2CX19xPr345dCsnyTF7MaT7/pqKYvR1OPu1EocD2icP0s5Ps/G+aX0LHbB35 gMVdkDO8Ddyv6atz Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 15 September 2015 21:43:19 Pingbo Wen wrote: > > On Tuesday, September 15, 2015 09:14 PM, Arnd Bergmann wrote: > > On Tuesday 15 September 2015 20:56:15 WEN Pingbo wrote: > >> The millisecond of the last second will be normal if tv_sec is > >> overflowed. But for y2038 consistency and demonstration purpose, > >> and avoiding further risks, we still need to fix it here, > >> to avoid similair problems. > >> > >> Signed-off-by: Pingbo Wen > >> Cc: Y2038 > >> Cc: linux-kernel@vger.kernel.org > >> Cc: Arnd Bergmann > >> Cc: Felipe Balbi > > > > I just replied to the thread of the first mail, and it's good to see you had > > the same thought about adding the usb folks to the Cc list. > > > > When sending a new version of a patch you have already sent before, it's > > common practice to use [PATCH v2] in the subject, so please do that for the > > next version. > > > > Ok, I thought previous thread is just draft, so I renewed one. Losing some history, > sorry for that. No, it's fine either way, I was just making sure you get the idea. > > > Your changelog text is better than the first version, but can still be improved. > > I would at least mention that we want to remove all uses of 'timeval' from > > device drivers in order to better scan for y2038 problems in the drivers that > > still use them. > > > > Also, you don't mention at all the discussion we had about real time vs. > > monotonic time for this driver. I think using monotonic time (ktime_get_ts64()) > > would be more appropriate here, but whichever you choose, you should explain > > in the changelog why you think that one is better than the other. > > Most of the time, we end up changing from real time to monotonic time in the > > same patch when converting a driver to avoid 32-bit time_t, so even you don't > > change it, you should explain why not. > > ktime_get_ts64() is another choice. As we discussed in previous thread, only using > jiffies can not keep the precise, and we should also handle the jiffies overflowing > case, so I kept the old implementation. Ok. As I said, it's most important to describe what the decision process was, rather than the specific decision (real time has worked fine in the past, so the change to monotonic is not critical here, just an additional improvement). Let's wait for more comments to the question whether the resolution should be changed for highspeed and superspeed mode, then you can post an updated version. Arnd