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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37D92C00A89 for ; Fri, 30 Oct 2020 08:50:55 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CD18E22210 for ; Fri, 30 Oct 2020 08:50:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD18E22210 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E77296E045; Fri, 30 Oct 2020 08:50:53 +0000 (UTC) Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by gabe.freedesktop.org (Postfix) with ESMTPS id 627B66E045 for ; Fri, 30 Oct 2020 08:50:52 +0000 (UTC) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id EE20B1F459F1; Fri, 30 Oct 2020 08:50:50 +0000 (GMT) Date: Fri, 30 Oct 2020 09:50:48 +0100 From: Boris Brezillon To: Tomi Valkeinen Subject: Re: [PATCH 3/5] drm: bridge: Propagate the bus flags from bridge->timings Message-ID: <20201030095048.2026d1d1@collabora.com> In-Reply-To: References: <20201016103917.26838-1-nikhil.nd@ti.com> <20201016103917.26838-4-nikhil.nd@ti.com> <20201028143453.njt3lak542wwx6jb@NiksLab> <20201029224817.GH15024@pendragon.ideasonboard.com> <20201030090815.7133637b@collabora.com> Organization: Collabora X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Swapnil Jakhade , Sekhar Nori , Laurent Pinchart , dri-devel@lists.freedesktop.org, Nikhil Devshatwar Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, 30 Oct 2020 10:40:46 +0200 Tomi Valkeinen wrote: > Hi Boris, > > On 30/10/2020 10:08, Boris Brezillon wrote: > > The "propagate output flags" and soon to be added "use > > timing->input_flags if present" logic should only be used as a fallback > > for bridges that do not support dynamic bus format/flags negotiation > > IMHO. Ideally we'd want to convert all bridges to do this dynamic bus > > format/flags negotiation and get rid of timings->input_bus_flags once > > this is done, but that's likely to take time. So, if your driver > > implements the ->atomic_check() hook and needs specific input flags, > > I'd recommend setting the input flags there instead of specifying it > > through timings->input_bus_flags. > > What is bus flags negotiation? Don't we have negotiation only for bus formats? Bus flags are just > set, and the previous bridge in the chain has to use those flags. Well, there's currently no such negotiation, but I don't see why there wouldn't be one at some point if bridges can configure it dynamically (in you A -> B example, A output flags must match B input flags, and if both A and B can configure those dynamically, they need to negotiate that part too). > > Or do you just refer to setting the bus flags dynamically in atomic_check, versus static in > input_bus_flags? Yes, that's what I suggest, even if those flags are static right now. _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel