From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756904AbeEJIKm (ORCPT ); Thu, 10 May 2018 04:10:42 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:34738 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756671AbeEJIKe (ORCPT ); Thu, 10 May 2018 04:10:34 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20180510081032euoutp010f223cf76be87c090b8b114e64234bcd~tOjFbA6o21361113611euoutp01L X-AuditID: cbfec7f4-6f9ff700000043e4-29-5af3fe76269d Subject: Re: [PATCH v2 26/26] drm/bridge: establish a link between the bridge supplier and consumer To: Peter Rosin , linux-kernel@vger.kernel.org Cc: Archit Taneja , Laurent Pinchart , David Airlie , Peter Senna Tschudin , Martin Donnelly , Martyn Welch , Gustavo Padovan , Maarten Lankhorst , Sean Paul , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , Kukjin Kim , Krzysztof Kozlowski , CK Hu , Philipp Zabel , Matthias Brugger , Rob Clark , Sandy Huang , =?UTF-8?Q?Heiko_St=c3=bcbner?= , Benjamin Gaignard , Vincent Abriou , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, Jyri Sarha , Daniel Vetter From: Andrzej Hajda Message-ID: Date: Thu, 10 May 2018 10:10:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180504135212.26977-27-peda@axentia.se> Content-Transfer-Encoding: 8bit Content-Language: en-US X-Brightmail-Tracker: H4sIAAAAAAAAA02SfUxTVxjGd+53O9pdqrPvdMu2IpuaiXOfJ2xDYxZz/9G5zCwLS5yd3hQn oOkVnCybrJBZKCgfjkHB+TEmpnGBoBQpA1nNWlssXcdAcSsQ6QKVMZkVAxnCWm7N+O93nud9 z/O+J4cjNWPMcm5P9gHRmK3P1DFKyu6a6VmbOxdJf7F0MhWX9ngIbDJP0Njk9DL4y3Y7i+ft 5ST+beoOg+tGfQi3DTui2q1xGp+o+BxXDJVR2FJkpvHYYIDCx0bGSez3N7HYZ/qLxUXl9Sxu HumncfllH4t7HXUM7i0IINwS/pvAd4fnSVzt7yTw6X9aKHzepcbdZxtJbCp8GQcHr1K4w3kS 4duhKRqPnp4mcbApGl9dGWbwtb4uamOSUNVVywq1+QFK6D1aSggPRq9TwqVgPRI67p+iBEvE SQpt1mC0xFxDC822Ikb4o/9HRmi9P0wL33reFYYsbkK4UH9YKPRcprZBuvLN3WLmnlzRuC5t pzKj8HqA3n9H++l8d3I+mtYUIwUH/Ctw90Y1W4yUnIY/h+BMwQ+EfLiH4OhPnXEngmDyZxv5 sOX4RBspGw0Ixi198aoJBKb8i6gYcdwSXoRzfetjDUv5DfB1f3jhWpL/TgmuIyE2ZjD8anhw YYCJsYpPg1Zn80ICxSeDrTO0oD/OfwCm0RlWrkkET02IirGCfw1KXGEUY5J/GgpaakmZtXAz dHIhDPhWBczafaw89tsw2d5IyLwEbrsvxvUnobuyhJL5MxgYM1FysxnB0L9HGNl4A664A3Rs MzI6daNjXQyBfwsayz+RUQ03JhLlEdRQYf+GlGUVmL+KP/WzMORrib+hFr7/ZYopQ0nWRYtZ Fy1jXbSM9f/YU4iyIa2YI2UZROmlbPFgiqTPknKyDSm79mU1o+j/755z37uEHLMfOxHPIV2C ajIhkq6h9bnSoSwnAo7ULVVN90Ql1W79oTzRuO8jY06mKDnRCo7SaVU7Vn2RruEN+gPiXlHc LxofugSnWJ6Pnhj0jlQZepd5nl9VdyUxwWtcuWmn4VVH9eHf01J93oMZT7mPbc7r/HDNloyS FcvsCqIpL/lXa42ro3ImuHmvRs16r26YrUla/cjWgrxxv+Ud9Rb/nymRru03Bx+7dv59267w e1Zp/pbwjLRxLhWXNVQ9+kJO0lnzjk3Ptb2+tqG9smNAR0kZ+vVrSKOk/w/671ft+wMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA02Sa0xTZxjH855bW0LNsaC8QRNNjTEusdIi9KlRxCWa88EPEj+4oJs2eAI4 eklPS4ThBGRbC4KAumlxVhM0BrfAyh0VmzrBithUFIKxQIAMK+MieEGDsNK6hG+//J//733y Jo+YlM3TseJMvZk36bVZciaC6lro9G+xLMymxk2+VUPpEw8BhdYJGgrdjxgouN0kgsWmChKe vZti4PJYN4LWobZgNjxOw++VJ6FysJyCEpuVhlcDPgrOjoyT4PXWiaC78F8R2CqqReAc6aWh 4l63CHraLjPQc9qHoDEwScDM0CIJF73tBFx700jBHx0roOtGLQmFRfHgH3hIwV23A8Hr0Xc0 jF2bI8FfF1x/8VyAgcfPXVTyBu5XV5WIq8r3UVxPWSnBfR7ro7gWfzXi7r6/SnEls26Sa7X7 gxXrJZpz1tgY7mXvHYZrfj9Ec1c8KdxgSSfB1Vef4oo896j9OFWxw2SwmPn1GQbBvFN+SAkq hVIDCtU2jUIZr/52uypBvjVpxzE+KzObN21NOqrIKOrz0capmBOLXRvz0ZysGEnEmN2Gz0+0 ksUoQixjryPs/ORA4UEMvu2YIMMched7i5lwaRxhR8GL0CCK5XHH7F8hIZrdhS/0BoglJtlb EbjhlS4sNCDc56pllgYMuxl/ru8PsZRNws1uZ+ghit2Ia9pHQ/kq9hs84J350lmJPZdGqSWW sIn4TEcAhRdswvNXnpJhXodPN1Z94Rj8YtRBlCOZfZluX6bYlyn2ZcpVRNWgaN4i6NJ1gkoh aHWCRZ+uSDPonCh4eU0dHxtaUPHkATdixUgeKZ2OnE2V0dpsIUfnRlhMyqOlc0+CkfSYNieX NxmOmCxZvOBGCcHPVZCxq9IMwTvWm48oE5Rq0CjV8er4RJDHSL1xOakyNl1r5r/neSNv+t8j xJLYfLTlt9enppo+qpk02Z6WO8Y1T639H4x7iaM/N45Ye/LeZK/dl+GZcQx6r2+WHH8wfPgX qr8+97Hm5k9k59fwp2/KNVxWdvAfyWqbd3fpIWMOm5ebtV7zd+IFW7lGdT7ZNfyDvu1TVHpd 863WwZRpcZxIUVK7q/J+QPdj4ndzKEW/do+cEjK0yq9Ik6D9D4pCfg6PAwAA X-CMS-MailID: 20180510081030eucas1p1e34df6d19674dded20ff11d48ff19368 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-MTR: 20180510081030eucas1p1e34df6d19674dded20ff11d48ff19368 X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20180504135432epcas3p368bb7541ca52bc8bc301dec794851214 X-RootMTR: 20180504135432epcas3p368bb7541ca52bc8bc301dec794851214 References: <20180504135212.26977-1-peda@axentia.se> <20180504135212.26977-27-peda@axentia.se> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.05.2018 15:52, Peter Rosin wrote: > If the bridge supplier is unbound, this will bring the bridge consumer > down along with the bridge. Thus, there will no longer linger any > dangling pointers from the bridge consumer (the drm_device) to some > non-existent bridge supplier. > > Signed-off-by: Peter Rosin > --- > drivers/gpu/drm/drm_bridge.c | 18 ++++++++++++++++++ > include/drm/drm_bridge.h | 2 ++ > 2 files changed, 20 insertions(+) > > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c > index 78d186b6831b..0259f0a3ff27 100644 > --- a/drivers/gpu/drm/drm_bridge.c > +++ b/drivers/gpu/drm/drm_bridge.c > @@ -26,6 +26,7 @@ > #include > > #include > +#include > #include > > #include "drm_crtc_internal.h" > @@ -127,12 +128,25 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, > if (bridge->dev) > return -EBUSY; > > + if (encoder->dev->dev != bridge->odev) { I wonder why device_link_add does not handle this case (self dependency) silently as noop, as it seems to be a correct behavior. > + bridge->link = device_link_add(encoder->dev->dev, > + bridge->odev, 0); > + if (!bridge->link) { > + dev_err(bridge->odev, "failed to link bridge to %s\n", > + dev_name(encoder->dev->dev)); > + return -EINVAL; > + } > + } > + > bridge->dev = encoder->dev; > bridge->encoder = encoder; > > if (bridge->funcs->attach) { > ret = bridge->funcs->attach(bridge); > if (ret < 0) { > + if (bridge->link) > + device_link_del(bridge->link); > + bridge->link = NULL; > bridge->dev = NULL; > bridge->encoder = NULL; > return ret; > @@ -159,6 +173,10 @@ void drm_bridge_detach(struct drm_bridge *bridge) > if (bridge->funcs->detach) > bridge->funcs->detach(bridge); > > + if (bridge->link) > + device_link_del(bridge->link); > + bridge->link = NULL; > + > bridge->dev = NULL; > } > > diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h > index b656e505d11e..804189c63a4c 100644 > --- a/include/drm/drm_bridge.h > +++ b/include/drm/drm_bridge.h > @@ -261,6 +261,7 @@ struct drm_bridge_timings { > * @list: to keep track of all added bridges > * @timings: the timing specification for the bridge, if any (may > * be NULL) > + * @link: drm consumer <-> bridge supplier Nitpick: "<->" suggests symmetry, maybe "device link from drm consumer to the bridge" would be better. Anyway: Reviewed-by: Andrzej Hajda  -- Regards Andrzej > * @funcs: control functions > * @driver_private: pointer to the bridge driver's internal context > */ > @@ -271,6 +272,7 @@ struct drm_bridge { > struct drm_bridge *next; > struct list_head list; > const struct drm_bridge_timings *timings; > + struct device_link *link; > > const struct drm_bridge_funcs *funcs; > void *driver_private;