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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 663F6C43467 for ; Mon, 12 Oct 2020 14:36:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 128E720838 for ; Mon, 12 Oct 2020 14:36:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="fkxMwduP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729790AbgJLOgA (ORCPT ); Mon, 12 Oct 2020 10:36:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388609AbgJLOf7 (ORCPT ); Mon, 12 Oct 2020 10:35:59 -0400 Received: from mail-wm1-x341.google.com (mail-wm1-x341.google.com [IPv6:2a00:1450:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22C89C0613D0 for ; Mon, 12 Oct 2020 07:35:59 -0700 (PDT) Received: by mail-wm1-x341.google.com with SMTP id b127so4943445wmb.3 for ; Mon, 12 Oct 2020 07:35:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-disposition:in-reply-to; bh=CS4OyMq4fS0Bhwsobzu7guLhX4olV/G/ClLkhuhMjgI=; b=fkxMwduPy7Mi/n+bV9EyV6Z1vJ1ek7B2dpi5Z+Cc1zoGQaPeAwtnD3hIUYpNwz8NNy grfTiephWpviO0XUTqemeoX5Fy0if/33WSQfHcs3Bnf5eC6FYLBpVWNoHVBL75gAP37l OLHc52gBx4Y8FnkvvzekCPn+IErOtdoHNRGKI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :in-reply-to; bh=CS4OyMq4fS0Bhwsobzu7guLhX4olV/G/ClLkhuhMjgI=; b=FoJd1alf4Qc1a5ZD8e+g7iN2BF/fsuyqHpqNb7zLu5XT3CiG/2GiQfckDHrKf5BJ0n 0dfZlSlAfkesX9uFgEY/glDHWc7exr3dedbmME6hYmmnwc7pObtBw5OkvJS9OiSmU8jY fM09rpFnDp/XeuD13gsyXVia+APcrYy46Npmnqc5lnfXPfeyUt03ZFhe1rEprbww51cc CP+JKheAEQYq6zMjDk8/PV8nmaTOyjWlPRa4gulM6hAQEt2jHRctOTjC0Q0Wp3UyjFHG gmcDK9RS3bIu5+KNeKNKk7r6f/xG7zu8TXz0EzywnSHgxHDB1JOWKcUXeaFv6FLgoF7x DxFA== X-Gm-Message-State: AOAM530159GwTb08aMlZaxiKWTf0XrGd6ZTbqY5fbxu0BCZeKT7qXlQH G8fy3arX1vB0DL73rcL8k3dm8A== X-Google-Smtp-Source: ABdhPJxGVuL+rWFfcFuPZBFAL6pDzTxq2Ad70ao8xyHZW6uniXqiGrdMDz9Voec37zpOONepDpbVBQ== X-Received: by 2002:a7b:c8c9:: with SMTP id f9mr2895067wml.162.1602513357830; Mon, 12 Oct 2020 07:35:57 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id 30sm15869709wrs.84.2020.10.12.07.35.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Oct 2020 07:35:56 -0700 (PDT) Date: Mon, 12 Oct 2020 16:35:55 +0200 From: Daniel Vetter To: Rob Clark Cc: dri-devel@lists.freedesktop.org, Daniel Vetter , Rob Clark , Sean Paul , David Airlie , "open list:DRM DRIVER FOR MSM ADRENO GPU" , "open list:DRM DRIVER FOR MSM ADRENO GPU" , open list Subject: Re: [PATCH v2 07/22] drm/msm: Do rpm get sooner in the submit path Message-ID: <20201012143555.GA438822@phenom.ffwll.local> Mail-Followup-To: Rob Clark , dri-devel@lists.freedesktop.org, Rob Clark , Sean Paul , David Airlie , "open list:DRM DRIVER FOR MSM ADRENO GPU" , "open list:DRM DRIVER FOR MSM ADRENO GPU" , open list References: <20201012020958.229288-1-robdclark@gmail.com> <20201012020958.229288-8-robdclark@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012020958.229288-8-robdclark@gmail.com> X-Operating-System: Linux phenom 5.7.0-1-amd64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Oct 11, 2020 at 07:09:34PM -0700, Rob Clark wrote: > From: Rob Clark > > Unfortunately, due to an dev_pm_opp locking interaction with > mm->mmap_sem, we need to do pm get before aquiring obj locks, > otherwise we can have anger lockdep with the chain: tbh this sounds like a bug in that subsystem, since it means we cannot use said subsystem in mmap handlers either. So if you have some remapping unit or need to wake up your gpu to blt the buffer into system memory first, we're toast. That doesn't sound right. So maybe Cc: pm folks and figure out how to fix this long term properly? Imo not a good reason to hold up this patch set, since unwrangling mmap_sem tends to be work ... -Daniel > > opp_table_lock --> &mm->mmap_sem --> reservation_ww_class_mutex > > For an explicit fencing userspace, the impact should be minimal > as we do all the fence waits before this point. It could result > in some needless resumes in error cases, etc. > > Signed-off-by: Rob Clark > --- > drivers/gpu/drm/msm/msm_gem_submit.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c > index 002130d826aa..a9422d043bfe 100644 > --- a/drivers/gpu/drm/msm/msm_gem_submit.c > +++ b/drivers/gpu/drm/msm/msm_gem_submit.c > @@ -744,11 +744,20 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, > > ret = submit_lookup_objects(submit, args, file); > if (ret) > - goto out; > + goto out_pre_pm; > > ret = submit_lookup_cmds(submit, args, file); > if (ret) > - goto out; > + goto out_pre_pm; > + > + /* > + * Thanks to dev_pm_opp opp_table_lock interactions with mm->mmap_sem > + * in the resume path, we need to to rpm get before we lock objs. > + * Which unfortunately might involve powering up the GPU sooner than > + * is necessary. But at least in the explicit fencing case, we will > + * have already done all the fence waiting. > + */ > + pm_runtime_get_sync(&gpu->pdev->dev); > > /* copy_*_user while holding a ww ticket upsets lockdep */ > ww_acquire_init(&submit->ticket, &reservation_ww_class); > @@ -825,6 +834,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data, > > > out: > + pm_runtime_put(&gpu->pdev->dev); > +out_pre_pm: > submit_cleanup(submit); > if (has_ww_ticket) > ww_acquire_fini(&submit->ticket); > -- > 2.26.2 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch