From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 054EBC4167B for ; Mon, 6 Nov 2023 10:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231206AbjKFK7j (ORCPT ); Mon, 6 Nov 2023 05:59:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229583AbjKFK7i (ORCPT ); Mon, 6 Nov 2023 05:59:38 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9AC8AB7; Mon, 6 Nov 2023 02:59:35 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 472F1223; Mon, 6 Nov 2023 11:59:13 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1699268353; bh=lhvz5saAeUdjlsIZ14t/fbtSNafXh2meA6GJnGK0o5o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p8wPSvFkU3F5WBwwM7QHtI1kB3IStSW2iy0ehDjUxEwxDPlEIJVeI/NDOzMEABskK Bn0aUm09ZZk9yMNhGO8QBjX4XaIy8DM0O8zXxiLQZ7qbxnehyjDkDDAGr1D8zWJYeN LS9W9Z8YM+w7YQyPtmVzOobwASF4TX9Q6gtSDAQg= Date: Mon, 6 Nov 2023 12:59:41 +0200 From: Laurent Pinchart To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Esker Wong Subject: Re: [PATCH] media: uvcvideo: Implement V4L2_EVENT_FRAME_SYNC Message-ID: <20231106105941.GB16995@pendragon.ideasonboard.com> References: <20231020-uvc-event-v1-1-3baa0e9f6952@chromium.org> <20231106103925.GA19272@pendragon.ideasonboard.com> <20231106104245.GB19272@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 06, 2023 at 11:51:06AM +0100, Ricardo Ribalda wrote: > On Mon, 6 Nov 2023 at 11:42, Laurent Pinchart wrote: > > On Mon, Nov 06, 2023 at 12:39:26PM +0200, Laurent Pinchart wrote: > > > On Fri, Oct 20, 2023 at 06:41:45AM +0000, Ricardo Ribalda wrote: > > > > Add support for the frame_sync event, so user-space can become aware > > > > earlier of new frames. > > > > > > > > Suggested-by: Esker Wong > > > > Tested-by: Esker Wong > > > > Signed-off-by: Ricardo Ribalda > > > > --- > > > > We have measured a latency of around 30msecs between frame sync > > > > and dqbuf. > > > > > > Not surprising, especially for large resolutions. I'm curious though, > > > what do you use this event for ? > > I think Esker is using it to get more accurate power measurements of > the camera stack. Esker, would you be able to provide more information ? > > > It's easy to miss the ++ there when reading the code, would the > > > following be more readable ? > > Actually that was my original code, but I thought you would like this better :) > > Thanks for the review, a v2 is on its way. Thank you. -- Regards, Laurent Pinchart