From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michel =?ISO-8859-1?Q?D=E4nzer?= Subject: Re: [RFC 4/4] drm: add support for raw monotonic vblank timestamps Date: Fri, 05 Oct 2012 16:14:07 +0200 Message-ID: <1349446447.17758.73.camel@thor.local> References: <1349444222-22274-1-git-send-email-imre.deak@intel.com> <1349444222-22274-5-git-send-email-imre.deak@intel.com> <1349445311.17758.69.camel@thor.local> <1349445544.17509.13.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1349445544.17509.13.camel@localhost> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Imre Deak Cc: Daniel Vetter , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Fre, 2012-10-05 at 16:59 +0300, Imre Deak wrote: = > On Fri, 2012-10-05 at 15:55 +0200, Michel D=E4nzer wrote: > > On Fre, 2012-10-05 at 16:37 +0300, Imre Deak wrote: = > > > In practice we never want the timestamps for vblank and page flip eve= nts > > > to be affected by time adjustments, so in addition to the gettimeofday > > > timestamps we used so far add support for raw monotonic timestamps. > > > = > > > For backward compatibility use flags to select between the old and new > > > timestamp format. > > > = > > > Note that with this change we will save the timestamp in both formats, > > > for cases where multiple clients are expecting an event notification = in > > > different time formats. > > = > > I wonder if all this trouble is really necessary. I honestly can't > > imagine any user of this API requiring non-monotonic timestamps and > > breaking with monotonic ones. I think it was simply a mistake that we > > didn't make them monotonic in the first place (or maybe it wasn't even > > possible when this API was first introduced). > = > Yea, I'd rather simply switch over to monotonic timestamps too. But that > would break apps that already compare against the wall time for whatever > purpose (for example A/V sync). Are there actually any such apps in the real world? Do they work when the wall time jumps? -- = Earthling Michel D=E4nzer | http://www.amd.com Libre software enthusiast | Debian, X and DRI developer