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 0AADDC001DF for ; Thu, 3 Aug 2023 20:45:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232080AbjHCUpA (ORCPT ); Thu, 3 Aug 2023 16:45:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230190AbjHCUo6 (ORCPT ); Thu, 3 Aug 2023 16:44:58 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D86A30EA for ; Thu, 3 Aug 2023 13:44:55 -0700 (PDT) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 625A58C1; Thu, 3 Aug 2023 22:43:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1691095428; bh=LWzMEFgrC/PlVsgJUx4AkW/o073y3IloiFtC+MVjNYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=htZTfD0VD+z3VFAZGYDuiQdDo5xVWEbeOBhNwfGKc9LSk3PLbSVgkCtCkjM/j9BxB 8E5WnhtCUzr1uXSi06u7uVCt7vB6c1QPpGZ7D0gtqlhSJXze9SobkS2nZtv1Qcnef/ l1oHArjkLnBuI+DbSS/WNT7hvS4yOlhpzZ/ukXSM= Date: Thu, 3 Aug 2023 23:44:59 +0300 From: Laurent Pinchart To: Simon Ser Cc: Dmitry Baryshkov , David Airlie , Daniel Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Andy Gross , Bjorn Andersson , Konrad Dybcio , Janne Grunau , Alex Deucher , Christian =?utf-8?B?S8O2bmln?= , "Pan, Xinhui" , Harry Wentland , Leo Li , Rodrigo Siqueira , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org Subject: Re: [PATCH 3/4] drm/uapi: document the USB subconnector type Message-ID: <20230803204459.GD27752@pendragon.ideasonboard.com> References: <20230729004913.215872-1-dmitry.baryshkov@linaro.org> <20230729004913.215872-4-dmitry.baryshkov@linaro.org> <20230802185547.GC32500@pendragon.ideasonboard.com> <20230802191351.GA1407@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 03, 2023 at 03:31:16PM +0000, Simon Ser wrote: > On Thursday, August 3rd, 2023 at 17:22, Simon Ser wrote: > > > The KMS docs describe "subconnector" to be defined as "downstream port" for DP. > > Can USB-C (or USB) be seen as a DP downstream port? > > To expand on this a bit: I'm wondering if we're mixing apples and > oranges here. The current values of "subconnector" typically describe > the lower-level protocol tunneled inside DP. For instance, VGA can be > tunneled inside the DP cable when using DP → VGA adapter. Doesn't this contradict the example use case you gave in your previous e-mail, with wlroots stating "DP-3 via DVI-D" ? I understand that as DP carried over a DVI-D physical connector, did I get it wrong ? > However, in the USB-C case, DP itself is tunneled inside USB-C. And you > might use a USB-C → DP adapter. So it's not really *sub*connector, it's > more of a *super*connector, right? > > I think [1] is somewhat related, since it also allows user-space to > discover whether a connector uses USB-C. But relying on sysfs to figure > this out isn't super optimal perhaps. > > [1]: https://lore.kernel.org/dri-devel/20221108185004.2263578-1-wonchung@google.com/ -- Regards, Laurent Pinchart