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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31B47C43381 for ; Mon, 11 Mar 2019 18:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07097206DF for ; Mon, 11 Mar 2019 18:48:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="kcTQJczS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728046AbfCKSso (ORCPT ); Mon, 11 Mar 2019 14:48:44 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:33303 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726942AbfCKSsn (ORCPT ); Mon, 11 Mar 2019 14:48:43 -0400 Received: by mail-ed1-f65.google.com with SMTP id d12so211756edp.0 for ; Mon, 11 Mar 2019 11:48:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=sender:date:from:to:cc:subject:message-id:mail-followup-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=f98+g+RT3l3DxvAAheGVVm6ONRnaMiYAzNdjej9J/g8=; b=kcTQJczSTaR5y45g5ENDYA5LjB94XNW9kGMcTV3SR/lSqgqzaz8wMqoSqD1kJpVSIW IaeJIjyRA2cf+hMSrrMGpNwQItRTXZqX/E69nTh8HMWt/n8Tm9vH/ROibLtPLVGcRWkk 1YK7vuh1NdCaglMOTN+RbYe8TZe54ky5kq6l8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to:user-agent; bh=f98+g+RT3l3DxvAAheGVVm6ONRnaMiYAzNdjej9J/g8=; b=pMb7/17cpg7wqHR9CYs3/RapB11xjIOz56VMYr34/pGA+15ciQAWEClgkQoRWgVxTB np66DCjm0+ujunXzzrGQPKx96s3j9wTwTQNHbLMfg/BPs8PWGxnHl9EpBGcznPIKvLo2 IVEz3oY4RpY01LGp3JSQh9FkmVHt5UcJdQ0JTbxfb5v4ZapCVC8GLQ/n0stP6ozv4TP7 zw18bjpeWkemedLAfnvIzNyoFm6HzVOtoNpMIkKjZtK83Adnsn2bL7aXoZdEZ0zqhjeK G24o/WFqobcbLlQY2YdiT5p6a8Tw8WtQ+5bLUqAGszlhocTOeujkd9wtTR0VyOb3zeUU zyyg== X-Gm-Message-State: APjAAAX0xTLBCgsFX4TAifVG3V+LEpnh1KjZEDvPFDg8oe6jriMHbDT4 WyvzWKnncTy4z6uagcp2DSw6lw== X-Google-Smtp-Source: APXvYqwujuAK5pq1B7bcSwZbNHECxMO+qRZwmgjMJkdKMqX3cV7GYWMWfMT5y8i9G4LAHD7dW8yV7A== X-Received: by 2002:a17:906:482:: with SMTP id f2mr22873401eja.68.1552330121958; Mon, 11 Mar 2019 11:48:41 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id s6sm4881237eda.90.2019.03.11.11.48.40 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Mar 2019 11:48:41 -0700 (PDT) Date: Mon, 11 Mar 2019 19:48:39 +0100 From: Daniel Vetter To: Rodrigo Siqueira Cc: Gerd Hoffmann , David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH] drm/bochs: Fix NULL dereference on atomic_disable helper Message-ID: <20190311184839.GO2665@phenom.ffwll.local> Mail-Followup-To: Rodrigo Siqueira , Gerd Hoffmann , David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org References: <20190310212150.xhhb4abzm7j3ain2@smtp.gmail.com> <20190311062200.4mtel3j5fjxtxrcf@sirius.home.kraxel.org> <20190311101159.t6mbzm5sdwuh5muc@smtp.gmail.com> <20190311130716.6hjqci43clic5lxx@sirius.home.kraxel.org> <20190311132358.GF2665@phenom.ffwll.local> <20190311133919.azyhtioxf23duf3g@sirius.home.kraxel.org> <20190311174958.xdw4lrvf6ydeplvc@smtp.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190311174958.xdw4lrvf6ydeplvc@smtp.gmail.com> X-Operating-System: Linux phenom 4.19.0-1-amd64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 11, 2019 at 02:49:58PM -0300, Rodrigo Siqueira wrote: > On 03/11, Gerd Hoffmann wrote: > > Hi, > > > > > > IIRC the drm code checks for the atomic_enable callback presence to > > > > figure whenever it should take the atomic or legacy code paths. > > > > > > It should check for drm_driver->mode_config.funcs.atomic_commit for that, > > > see drm_drv_uses_atomic_modeset(). Anything else should be a bug. > > > > > > Or do you mean the fallback to the old crtc helper prepare/commit > > > callbacks? > > > > Probably the later. There was some reason why I've left in the empty > > bochs_crtc_atomic_enable() callback ... > > Just for checking before I start to work in this patch: > The correct solution should be made atomic_enable and atomic_disable > optional, right? I should do it, and check if Bochs driver really needs > bochs_crtc_atomic_enable after my change, right? Yup. I just tried to remember why we haven't done this yet, but I think that was a patch to make crtc->helper_funcs optional. And that doesn't make sense imo, since if your crtc doesn't do anything then you don't really have an atomic driver :-) And if there's ever a legit use case for this, then that drive probably shouldn't use the atomic helpers ... But making crtc_helper_funcs->atomic_enable/disable optional sounds like a good idea. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch