Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754308AbdFPOn7 (ORCPT ); Fri, 16 Jun 2017 10:43:59 -0400 Received: from anholt.net ([50.246.234.109]:35492 "EHLO anholt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752095AbdFPOnz (ORCPT ); Fri, 16 Jun 2017 10:43:55 -0400 From: Eric Anholt To: Archit Taneja , dri-devel@lists.freedesktop.org, Andrzej Hajda , Laurent Pinchart , Thierry Reding , Rob Herring , Mark Rutland , devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/7] drm/bridge: Support hotplugging panel-bridge. In-Reply-To: <777ee1b1-e5ce-ea29-8a48-f792354a22d1@codeaurora.org> References: <20170615204130.19255-1-eric@anholt.net> <20170615204130.19255-2-eric@anholt.net> <777ee1b1-e5ce-ea29-8a48-f792354a22d1@codeaurora.org> User-Agent: Notmuch/0.22.2+1~gb0bcfaa (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Fri, 16 Jun 2017 07:43:52 -0700 Message-ID: <871sqkouvr.fsf@eliezer.anholt.net> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2062 Lines: 48 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Archit Taneja writes: > On 06/16/2017 02:11 AM, Eric Anholt wrote: >> If the panel-bridge is being set up after the drm_mode_config_reset(), >> then the connector's state would never get initialized, and we'd >> dereference the NULL in the hotplug path. We also need to register >> the connector, so that userspace can get at it. >>=20 > > Shouldn't the KMS driver make sure the panel-bridge is set up before > drm_mode_config_reset? Is it the case when we're inserting the > panel-bridge driver as a module? > > > All the connectors that have been added are registered automatically > when drm_dev_register() is called by the KMS driver. Registering a > connector in the middle of setting up our driver is prone to race > conditions if the userspace decides to use them immediately. Yeah, this is fixing initializing panel_bridge at DSI host_attach time, which in the case of a panel module that creates the DSI device (adv7533-style, like you said I should use as a reference) will be after drm_mode_config_reset() and drm_dev_register(). --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/JuuFDWp9/ZkuCBXtdYpNtH8nugFAllD7qgACgkQtdYpNtH8 nuh12hAAtxtxVUCKAiczE4dENEjJAiemAFSkWhvTsOQOi12aUHBOvMn/jojekhSL P+XDg8uBd9ryGQh7hNo0uMkzWD6ps75C0mZpykkuz7Fho6b48VCKv0cFCxVHJu5o 3s7kmxth/v73Qedn98XIMgnfqBJv8xSodii4J1HTBBvOTXTVy28Vzm4QCfZ+Ow5M qGcgdT0u/zlI+Q21VZdk4wpLEmsyp9RNyrzFjGrb+uX4Mv46eLnBdw29NZbqOODU 8LAvMSPWmttfbN8NHFjojffFpiEKld3QWuoG1Xa7LeC4MT7HNfjoQzj98r0mw1zX QP2FY+v8HYBvuyUrbWtS9GMPcqW/TXtBIWN+0YZ1IX4HpY5RinyZufPzL7rR8aWo o6fsa+OAgKjXz8QJbqEcL1hZOaOUKTopWiKpXFgBaYYXoFdgrmCWOL0mh9LQYKMc 1+UZovu/RepCIO1Qq5vUz3TDKsl48WQVG+v8qEHVKh7MdfSVWhLt0urYvo5NXCmX uOZ2pRzqOO5Zxhumm1OCyv+G6uQlVXcP2655U6sq1uaHdiIYw0qqEgZk3lo56Xjk B6EHR9TrPUs/CCRFAoSz+0QVCJ0PkQ5GH+qoaayxE8vLJeGhIUD6KZdbNqJYDADm H+0WGm/qbxJDzQtXbc1nceuKjZLutboDw7fEkwEaxfEnuZlaAxE= =M+WK -----END PGP SIGNATURE----- --=-=-=--