From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH v2 3/4] input: Deprecate real timestamps beyond year 2106 Date: Wed, 26 Oct 2016 19:24:20 -0700 Message-ID: <20161027022420.GC31660@dtor-ws> References: <1476761253-13450-1-git-send-email-deepa.kernel@gmail.com> <1476761253-13450-4-git-send-email-deepa.kernel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <1476761253-13450-4-git-send-email-deepa.kernel@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: y2038-bounces@lists.linaro.org Sender: "Y2038" To: Deepa Dinamani Cc: Jiri Kosina , arnd@arndb.de, Hans de Goede , y2038@lists.linaro.org, linux-kernel@vger.kernel.org, Peter Hutterer , Benjamin Tissoires , linux-input@vger.kernel.org List-Id: linux-input@vger.kernel.org SGkgRGVlcGEsCgpPbiBNb24sIE9jdCAxNywgMjAxNiBhdCAwODoyNzozMlBNIC0wNzAwLCBEZWVw YSBEaW5hbWFuaSB3cm90ZToKPiBzdHJ1Y3QgdGltZXZhbCBpcyBub3QgeTIwMzggc2FmZS4KPiBB bGwgdXNhZ2Ugb2YgdGltZXZhbCBpbiB0aGUga2VybmVsIHdpbGwgYmUgcmVwbGFjZWQgYnkKPiB5 MjAzOCBzYWZlIHN0cnVjdHVyZXMuCj4gCj4gc3RydWN0IGlucHV0X2V2ZW50IG1haW50YWlucyB0 aW1lIGZvciBlYWNoIGlucHV0IGV2ZW50Lgo+IFJlYWwgdGltZSB0aW1lc3RhbXBzIGFyZSBub3Qg aWRlYWwgZm9yIGlucHV0IGFzIHRoaXMKPiB0aW1lIGNhbiBnbyBiYWNrd2FyZHMgYXMgbm90ZWQg aW4gdGhlIHBhdGNoIGE4MGI4M2I3YjgKPiBieSBKb2huIFN0dWx0ei4gSGVuY2UsIGhhdmluZyB0 aGUgaW5wdXRfZXZlbnQudGltZSBmaWVsZHMKPiBvbmx5IGJpZyBlbm91Z2ggZm9yIG1vbm90b25p YyBhbmQgYm9vdCB0aW1lcyBhcmUKPiBzdWZmaWNpZW50Lgo+IAo+IExlYXZlIHRoZSBvcmlnaW5h bCBpbnB1dF9ldmVudCBhcyBpcy4gVGhpcyBpcyB0byBtYWludGFpbgo+IGJhY2t3YXJkIGNvbXBh dGliaWxpdHkgd2l0aCBleGlzdGluZyB1c2Vyc3BhY2UgaW50ZXJmYWNlcwo+IHRoYXQgdXNlIGlu cHV0X2V2ZW50Lgo+IEludHJvZHVjZSBhIG5ldyByZXBsYWNlbWVudCBzdHJ1Y3QgcmF3X2lucHV0 X2V2ZW50Lgo+IFRoaXMgcmVwbGFjZXMgdGltZXZhbCB3aXRoIHN0cnVjdCBpbnB1dF90aW1ldmFs LiBUaGlzIHN0cnVjdHVyZQo+IG1haW50YWlucyB0aW1lIGluIF9fa2VybmVsX3Vsb25nX3Qgb3Ig Y29tcGF0X3Vsb25nX3QgdG8gYWxsb3cKPiBmb3IgYXJjaGl0ZWN0dXJlcyB0byBvdmVycmlkZSB0 eXBlcyBhcyBpbiB0aGUgY2FzZSBvZiB4MzIuCj4gCj4gVGhlIGNoYW5nZSByZXF1aXJlcyBhbnkg dXNlcnNwYWNlIHV0aWxpdGllcyByZWFkaW5nIG9yIHdyaXRpbmcKPiBmcm9tIGV2ZW50IG5vZGVz IHRvIHVwZGF0ZSB0aGVpciByZWFkaW5nIGZvcm1hdCB0byBtYXRjaAo+IHJhd19pbnB1dF9ldmVu dC4gVGhlIGNoYW5nZXMgdG8gdGhlIHBvcHVsYXIgbGlicmFyaWVzIHdpbGwgYmUKPiBwb3N0ZWQg YWxvbmcgd2l0aCB0aGUga2VybmVsIGNoYW5nZXMuCj4gVGhlIGRyaXZlciB2ZXJzaW9uIGlzIGFs c28gdXBkYXRlZCB0byByZWZsZWN0IHRoZSBjaGFuZ2UgaW4KPiBldmVudCBmb3JtYXQuCgpJZiB1 c2VycyBhcmUgZm9yY2VkIHRvIHVwZGF0ZSB0byBhZGFwdCB0byB0aGUgbmV3IGV2ZW50IGZvcm1h dCwgc2hvdWxkCndlIGNvbnNpZGVyIG1vcmUgcmFkaWNhbCBjaGFuZ2VzPyBGb3IgZXhhbXBsZSwg ZG9lcyBpdCBtYWtlIHNlbnNlIHRvCnNlbmQgdGltZXN0YW1wIG9uIGV2ZXJ5IGV2ZW50PyBNYXli ZSB3ZSBzaG91bGQgb25seSBzZW5kIGl0IG9uY2UgcGVyCmV2ZW50IHBhY2tldCAoYmV0d2VlbiBF Vl9TWU4vU1lOX1JFUE9SVCk/IFdoYXQgZ3JhbnVsYXJpdHkgZG8gd2UgbmVlZD8KSXMgdGhlcmUg YW55dGhpbmcgZWxzZSBpbiBjdXJyZW50IHByb3RvY29sIHRoYXQgd2UnZCBsaWtlIHRvIGNoYW5n ZT8KClRoYW5rcy4KCi0tIApEbWl0cnkKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX18KWTIwMzggbWFpbGluZyBsaXN0ClkyMDM4QGxpc3RzLmxpbmFyby5vcmcK aHR0cHM6Ly9saXN0cy5saW5hcm8ub3JnL21haWxtYW4vbGlzdGluZm8veTIwMzgK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935546AbcJ0CY1 (ORCPT ); Wed, 26 Oct 2016 22:24:27 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:33622 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932239AbcJ0CYY (ORCPT ); Wed, 26 Oct 2016 22:24:24 -0400 Date: Wed, 26 Oct 2016 19:24:20 -0700 From: Dmitry Torokhov To: Deepa Dinamani Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, arnd@arndb.de, y2038@lists.linaro.org, Peter Hutterer , Benjamin Tissoires , Jiri Kosina , Hans de Goede Subject: Re: [PATCH v2 3/4] input: Deprecate real timestamps beyond year 2106 Message-ID: <20161027022420.GC31660@dtor-ws> References: <1476761253-13450-1-git-send-email-deepa.kernel@gmail.com> <1476761253-13450-4-git-send-email-deepa.kernel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1476761253-13450-4-git-send-email-deepa.kernel@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Deepa, On Mon, Oct 17, 2016 at 08:27:32PM -0700, Deepa Dinamani wrote: > struct timeval is not y2038 safe. > All usage of timeval in the kernel will be replaced by > y2038 safe structures. > > struct input_event maintains time for each input event. > Real time timestamps are not ideal for input as this > time can go backwards as noted in the patch a80b83b7b8 > by John Stultz. Hence, having the input_event.time fields > only big enough for monotonic and boot times are > sufficient. > > Leave the original input_event as is. This is to maintain > backward compatibility with existing userspace interfaces > that use input_event. > Introduce a new replacement struct raw_input_event. > This replaces timeval with struct input_timeval. This structure > maintains time in __kernel_ulong_t or compat_ulong_t to allow > for architectures to override types as in the case of x32. > > The change requires any userspace utilities reading or writing > from event nodes to update their reading format to match > raw_input_event. The changes to the popular libraries will be > posted along with the kernel changes. > The driver version is also updated to reflect the change in > event format. If users are forced to update to adapt to the new event format, should we consider more radical changes? For example, does it make sense to send timestamp on every event? Maybe we should only send it once per event packet (between EV_SYN/SYN_REPORT)? What granularity do we need? Is there anything else in current protocol that we'd like to change? Thanks. -- Dmitry