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 ABB93FA3740 for ; Thu, 27 Oct 2022 01:58:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232906AbiJ0B6y (ORCPT ); Wed, 26 Oct 2022 21:58:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233244AbiJ0B6x (ORCPT ); Wed, 26 Oct 2022 21:58:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB689C696C; Wed, 26 Oct 2022 18:58:52 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 9B63CB8248E; Thu, 27 Oct 2022 01:58:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D448C433D6; Thu, 27 Oct 2022 01:58:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1666835930; bh=7XhdauFWmszF7qH8F0omcebe1A7UMyRAwOUOW2AS3dc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CED3jK+ZPtWwB7wTRjdVm/OSrbwnVVIOeWLJ+vD+0MMV2wyvLtq8gRgHeE+CA0QB0 bNsdyqlGcLYyL6lbqdwC8YWx6yvjrFNzxpofNIM9t7PuMg7IKiGa6OFkqdfEG0AMFm oSZ98AQjfIjO+nijtAi2DQHwAWXkAR41NQrZnGer0s5l3256WvxzGeXj1EhsqhZK9X uqfkxxLNWm7C22fN0m926Tol7qdGDrS4D7dGkYzBK+OEml/7g6Ta+/swo9Dch/1U2M Yk0O+0w7mnIU8fnXNy6k2oYIrZXpBbwK50/srC5yzL7fC5uD6d85t39RfDOdUsmKiu BYun4RlHCjPxA== Date: Wed, 26 Oct 2022 20:58:46 -0500 From: Bjorn Andersson To: Dmitry Baryshkov Cc: Bjorn Andersson , Rob Clark , Abhinav Kumar , Sean Paul , David Airlie , Daniel Vetter , Rob Herring , Krzysztof Kozlowski , Konrad Dybcio , Kuogee Hsieh , Sankeerth Billakanti , Johan Hovold , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 09/12] drm/msm/dp: HPD handling relates to next_bridge Message-ID: <20221027015846.5gsmlinx4iwyjvui@builder.lan> References: <20221026032624.30871-1-quic_bjorande@quicinc.com> <20221026032624.30871-10-quic_bjorande@quicinc.com> <5974CB5A-699F-4768-9DAA-FAE507CFAD53@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5974CB5A-699F-4768-9DAA-FAE507CFAD53@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed, Oct 26, 2022 at 09:08:49AM +0300, Dmitry Baryshkov wrote: > > > On 26 October 2022 06:26:21 EEST, Bjorn Andersson wrote: > >From: Bjorn Andersson > > > >The DisplayPort controller's internal HPD interrupt handling is used for > >cases where the HPD signal is connected to a GPIO which is pinmuxed into > >the DisplayPort controller. > > > >Most of the logic for enabling and disabling the HPD-related interrupts > >is conditioned on the presence of an EDP panel, but more generically > >designs that has a downstream drm_bridge (next_bridge) could use this to > >handle the HPD interrupts, instead of the internal mechanism. > > > >So replace the current is_edp-based guards with a check for the presence > >of next_bridge. > > This does not sound correct. The next bridge might be a dummy bridge, > not supporting the hpd. I only considered checking for the Chrome case, where the output isn't modelled and we have to rely on the internal HPD logic. Checking that next_bridge is present and will deliver us hpd events sounds somewhat reasonable. But if I understand the code correctly, panel-edp isn't handing us hpd events - and we still don't want the internal HPD logic to trigger. So I presume I would need to check that this isn't a EDP controller and that we're going to get external HPD events? If so, clean you please give me some pointer on how to check if next_bridge will provide us with hpd signaling or not? PS. Which dummy bridge do you have in mind? > Please change this to use the enable_hpd()/disable_hpd() callbacks. > This way the drm_bridge_connector framework will make sure to enable > hpd handling for the bridge that is actually supposed to generate hpd > events. > The drm_bridge_connector_init() call in dp_drm_connector_init() does this for us already. Regards, Bjorn > > > > >Signed-off-by: Bjorn Andersson > >Signed-off-by: Bjorn Andersson > >--- > > > >Changes since v2: > >- None > > > -- > With best wishes > Dmitry