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_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 28FD7C433E1 for ; Fri, 7 Aug 2020 08:57:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 018BF206B5 for ; Fri, 7 Aug 2020 08:57:48 +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="P5BLbM7N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727813AbgHGI5r (ORCPT ); Fri, 7 Aug 2020 04:57:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbgHGI5p (ORCPT ); Fri, 7 Aug 2020 04:57:45 -0400 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 265A8C061575 for ; Fri, 7 Aug 2020 01:57:45 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id k20so1101661wmi.5 for ; Fri, 07 Aug 2020 01:57:45 -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=H73Msn3ig8oo+rXLBRFR40qhkjSySvB7pfbrGJDIkto=; b=P5BLbM7NaQMP5e2hJpp/jGb9n9cEXDqguDO01xB7EI9UcQR7OyzK98j0PVhTipFk+W TQ70UzqxnBDEJangW88G9Dq+lqyXD9Rf/jm+IVd7toPT5l6IrZDIoKO127KmFgkwabTs W14uS0QIQXZq8BKcRvIVDm4eJj+ZOC+728qNQ= 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=H73Msn3ig8oo+rXLBRFR40qhkjSySvB7pfbrGJDIkto=; b=URH7hwcx8rrtfzjcEy+CTCMj1tMSIdF83o1Wf9BXn1Wse4biypKgDc6aPyyW+H9S0Z NQTytvNkPZk6JV2NwdEbU7Wk1V1NEHJQMQ5d59haar6pCQNFVbTOwO/zy8hNPOpj992F /+zLm2mkPyPaRJCUvxul9pLiJPf4PfbW9K8sRhrQWUrlHBX0NRkLb082uLzU1krFuJou 2n6uxazUCAosj436NNh0KyVKLPKItSZDsJtoefOUY+SsXqQWJxLw1T5evZXo9V2H+AcG Bq/dFx0zlYdFDY5jT7w9ULMQRAk5bU0FhJjmWVAeTPeDqYyJdCPLbo6JKvH5QadWF2mM 6+pA== X-Gm-Message-State: AOAM531JhKuq9rDszpboJ3wd+gZqC39Qj7hZxL3/rO2vFtXT71HlJpIN b1bN27MiFAbnMsiSIkzg9Vizig== X-Google-Smtp-Source: ABdhPJynkqQfgSYGXyIhXXRsLuU2JaYCqT62Ezi3rAu3TCxoggostYXPfA0lWy6VQU0lDkGUgE8khA== X-Received: by 2002:a1c:df02:: with SMTP id w2mr12869666wmg.137.1596790663593; Fri, 07 Aug 2020 01:57:43 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id o30sm9643520wra.67.2020.08.07.01.57.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Aug 2020 01:57:42 -0700 (PDT) Date: Fri, 7 Aug 2020 10:57:40 +0200 From: daniel@ffwll.ch Cc: Kalyan Thota , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Krishna Manikandan , linux-arm-msm , Raviteja Tamatam , Linux Kernel Mailing List , dri-devel , Douglas Anderson , Sean Paul , Abhinav Kumar , Drew Davenport , "Kristian H. Kristensen" , Stephen Boyd , freedreno Subject: Re: [v1] drm/msm/dpu: Fix reservation failures in modeset Message-ID: <20200807085740.GR6419@phenom.ffwll.local> Mail-Followup-To: Rob Clark , Kalyan Thota , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Krishna Manikandan , linux-arm-msm , Raviteja Tamatam , Linux Kernel Mailing List , dri-devel , Douglas Anderson , Sean Paul , Abhinav Kumar , Drew Davenport , "Kristian H. Kristensen" , Stephen Boyd , freedreno References: <1596634446-1413-1-git-send-email-kalyan_t@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.7.0-1-amd64 To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 05, 2020 at 08:48:34AM -0700, Rob Clark wrote: > On Wed, Aug 5, 2020 at 6:34 AM Kalyan Thota wrote: > > > > In TEST_ONLY commit, rm global_state will duplicate the > > object and request for new reservations, once they pass > > then the new state will be swapped with the old and will > > be available for the Atomic Commit. > > > > This patch fixes some of missing links in the resource > > reservation sequence mentioned above. > > > > 1) Creation of a duplicate state in test_only commit (Rob) > > 2) Allow resource release only during crtc_active false. > > > > For #2 > > In a modeset operation, swap state happens well before disable. > > Hence clearing reservations in disable will cause failures > > in modeset enable. > > > > Sequence: > > Swap state --> old, new > > modeset disables --> virt disable > > modeset enable --> virt modeset > > > > Allow reservations to be cleared only when crtc active is false > > as in that case there wont be any modeset enable after disable. > > > > Signed-off-by: Kalyan Thota > > --- > > drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 7 +++++-- > > 1 file changed, 5 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > > index 63976dc..b85a576 100644 > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c > > @@ -582,7 +582,7 @@ static int dpu_encoder_virt_atomic_check( > > dpu_kms = to_dpu_kms(priv->kms); > > mode = &crtc_state->mode; > > adj_mode = &crtc_state->adjusted_mode; > > - global_state = dpu_kms_get_existing_global_state(dpu_kms); > > + global_state = dpu_kms_get_global_state(crtc_state->state); > > trace_dpu_enc_atomic_check(DRMID(drm_enc)); > > > > /* > > @@ -1172,6 +1172,7 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc) > > struct msm_drm_private *priv; > > struct dpu_kms *dpu_kms; > > struct dpu_global_state *global_state; > > + struct drm_crtc_state *crtc_state; > > int i = 0; > > > > if (!drm_enc) { > > @@ -1191,6 +1192,7 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc) > > priv = drm_enc->dev->dev_private; > > dpu_kms = to_dpu_kms(priv->kms); > > global_state = dpu_kms_get_existing_global_state(dpu_kms); > > + crtc_state = drm_enc->crtc->state; > > > > trace_dpu_enc_disable(DRMID(drm_enc)); > > > > @@ -1220,7 +1222,8 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc) > > > > DPU_DEBUG_ENC(dpu_enc, "encoder disabled\n"); > > > > - dpu_rm_release(global_state, drm_enc); > > + if (crtc_state->active_changed && !crtc_state->active) > > + dpu_rm_release(global_state, drm_enc); > > I still think releasing the state in the atomic_commit() path is the > wrong thing to do. In the commit path, the various state objects > should be immutable.. ie. in the atomic_test() path you derive the new > hw state (including assignment/release of resources), and > atomic_commit() is simply pushing the state down to the hw. > > Otherwise, this looks better than v1. Yeah this races and is total no-go. If you touch your state in commit (except some very specific exceptions), then a next TEST_ONLY atomic_check might duplicate the atomic state object in an incosistent state, and fail. Worse, this looks like if you race like that then you might duplicate an object with old reservations still in place, and then we've essentially leaked those resources and need to reboot. Yes most compositors use blocking modesets, but some actually do full nonblocking modesets. This stuff needs to be moved into the atomic_check code, and your commit code needs to be careful to use the right state (old or new) when pushing it into hw. Cheers, Daniel > > BR, > -R > > > > > mutex_unlock(&dpu_enc->enc_lock); > > } > > -- > > 1.9.1 > > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch