Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934097AbcCHAGP (ORCPT ); Mon, 7 Mar 2016 19:06:15 -0500 Received: from mail-vk0-f47.google.com ([209.85.213.47]:33246 "EHLO mail-vk0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934044AbcCHAFt (ORCPT ); Mon, 7 Mar 2016 19:05:49 -0500 MIME-Version: 1.0 In-Reply-To: <20160306162951.GA14170@phenom.ffwll.local> References: <1457135033-11791-1-git-send-email-dianders@chromium.org> <20160306162951.GA14170@phenom.ffwll.local> Date: Mon, 7 Mar 2016 16:05:48 -0800 X-Google-Sender-Auth: twBEO7xJ9pUV89BvwCOznYdBe38 Message-ID: Subject: Re: [PATCH] drm: Check for connector->state NULL in drm_atomic_add_affected_connectors From: Doug Anderson To: Douglas Anderson , David Airlie , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , Tomasz Figa , =?UTF-8?B?5aea5pm65oOF?= , =?UTF-8?Q?Heiko_St=C3=BCbner?= Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2068 Lines: 45 Daniel, On Sun, Mar 6, 2016 at 8:29 AM, Daniel Vetter wrote: > On Fri, Mar 04, 2016 at 03:43:53PM -0800, Douglas Anderson wrote: >> On a system I'm doing development on I found a crash. The crawl looked >> like: >> >> PC is at drm_atomic_add_affected_connectors+0x98/0xe8 >> ... >> drm_atomic_add_affected_connectors from __drm_atomic_helper_set_config+0x218/0x344 >> __drm_atomic_helper_set_config from restore_fbdev_mode+0x108/0x250 >> restore_fbdev_mode from drm_fb_helper_restore_fbdev_mode_unlocked+0x3c/0x80 >> drm_fb_helper_restore_fbdev_mode_unlocked from rockchip_drm_lastclose+0x1c/0x20 >> rockchip_drm_lastclose from drm_lastclose+0x4c/0x104 >> drm_lastclose from drm_release+0x424/0x47c >> drm_release from __fput+0xf8/0x1d4 >> __fput from ____fput+0x18/0x1c >> ____fput from task_work_run+0xa8/0xbc >> task_work_run from do_exit+0x448/0x91c >> do_exit from do_group_exit+0x5c/0xcc >> do_group_exit from get_signal+0x4dc/0x57c >> get_signal from do_signal+0x9c/0x3b4 >> do_signal from do_work_pending+0x60/0xb8 >> do_work_pending from slow_work_pending+0xc/0x20 >> >> I found that I could fix the crash by checking connector->state against >> NULL. This isn't code I'm familiar with and I didn't dig too deep, so >> I'd appreciate any opinions about whether this is a sane thing to do. >> Note that I don't actually have graphics up on my system at the moment, >> so perhaps this is all just a symptom of the strange state I'm in. >> >> Signed-off-by: Douglas Anderson > > This is a driver bug - under atomic the assumption is that there is > _always_ a current software state. Most driver set up the initial > "everything off" state in the ->reset functions. Ah, I see what the problem is. It looks like the main Rockchip subsystem moved to atomic but the patch to support that in dw_hdmi never landed. If I pick then my crash goes away. :) In case it's not obvious, please consider $SUBJECT patch abandoned. Thanks! -Doug