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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 38732C43457 for ; Fri, 16 Oct 2020 15:13:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA43720874 for ; Fri, 16 Oct 2020 15:13:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bw0C7RL0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409823AbgJPPNh (ORCPT ); Fri, 16 Oct 2020 11:13:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409810AbgJPPNg (ORCPT ); Fri, 16 Oct 2020 11:13:36 -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 5401AC061755; Fri, 16 Oct 2020 08:13:36 -0700 (PDT) Received: by mail-wm1-x341.google.com with SMTP id e2so3355324wme.1; Fri, 16 Oct 2020 08:13:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=4caXpkclqb0kte1ui2rZGOT3gO9tw5QkWF6WaM5340U=; b=bw0C7RL0+fhKMO0EAe8XGEcHwb8wyybaCpfl8P7sGnfdkZI9j4tysI6uZ0YoR29/ha YOX4aILlakJ066q+xevlet5l+Z+N9q/nV7+KQ/NKKo3PoqCwvkqKc4MR4ryRAmfVyqTJ uz9QwYlBWj2ZUFkyZ/iB50AZoKJOmHEFk3aQyW2Q+ljkXeftI1rA7efNHa+FZThIiT4K wnmZSuOqxrB01w27tBcLSH/JQmZ6evhSO/vqsZliSKtLWCHF4Bm+V6PvS55UoVIl4rIy DKgs589sQo9GoZg5GOugVRSrxKtqGwZuZqZxIpdhnOn/1/ZjONqYyoPkPZqi0JtPd9tA H/bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4caXpkclqb0kte1ui2rZGOT3gO9tw5QkWF6WaM5340U=; b=URbglXgCr8xtVv0EEkKQ0fcCFjJHrE24DHS/T3tmMgzSK6jhpfEH1K4+KvUlmynPC6 WlV7eG3ZxdDaiA0+Ail4WK41i2OliIHKpd5P1zpNZQh01pbgnZCX7g+U/78QBhHWZaHV PW3exzLKDJgcGxdOuw7NojZyyMDGBECKAbfYGtEm29Ki5lWu1Y7n+Ss42TQ6MTY2p11G Wibe0Xf1+aR555EIfMQNrNt0QbAu8gUgCbPuOUg49+/sJEHOrbrrcuV1n2IOInt592r4 uD8CRJu9RJU3WfMEFG5iyhlFYMe2FtzdZ7Xorv3jLwIQwvxYeXnofJ7kgRF/6frt/lR8 tF3w== X-Gm-Message-State: AOAM5315qmZa+Nx4ZGrLD0ZPM38bRZBjAat2Qh2diZJ9f46x5OpOjXiV FHZNwVwhHI83Vz0+8dZsBRrP39eptYnsKe6MzYDIQPxKUWs= X-Google-Smtp-Source: ABdhPJzr3VYyUdzLIDtBlIsdA+pEKl3QsosK5nMd+7onCOzT6+6p6L4hMZjIv11pJzsNcjZWS7NXyiKQkqyJvnToGuo= X-Received: by 2002:a05:600c:2241:: with SMTP id a1mr4437272wmm.49.1602861212981; Fri, 16 Oct 2020 08:13:32 -0700 (PDT) MIME-Version: 1.0 References: <1602857443-27317-1-git-send-email-mkrishn@codeaurora.org> In-Reply-To: <1602857443-27317-1-git-send-email-mkrishn@codeaurora.org> From: Rob Clark Date: Fri, 16 Oct 2020 08:13:18 -0700 Message-ID: Subject: Re: [v3] drm/msm: Fix race condition in msm driver with async layer updates To: Krishna Manikandan Cc: dri-devel , linux-arm-msm , freedreno , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Linux Kernel Mailing List , Sean Paul , "Kristian H. Kristensen" , Kalyan Thota , Douglas Anderson Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri, Oct 16, 2020 at 7:11 AM Krishna Manikandan wrote: > > When there are back to back commits with async cursor update, > there is a case where second commit can program the DPU hw > blocks while first didn't complete flushing config to HW. > > Synchronize the compositions such that second commit waits > until first commit flushes the composition. > > This change also introduces per crtc commit lock, such that > commits on different crtcs are not blocked by each other. > > Changes in v2: > - Use an array of mutexes in kms to handle commit > lock per crtc. (Rob Clark) > > Changes in v3: > - Add wrapper functions to handle lock and unlock of > commit_lock for each crtc. (Rob Clark) > > Signed-off-by: Krishna Manikandan Reviewed-by: Rob Clark > --- > drivers/gpu/drm/msm/msm_atomic.c | 37 ++++++++++++++++++++++++------------- > drivers/gpu/drm/msm/msm_kms.h | 6 ++++-- > 2 files changed, 28 insertions(+), 15 deletions(-) > > diff --git a/drivers/gpu/drm/msm/msm_atomic.c b/drivers/gpu/drm/msm/msm_atomic.c > index 561bfa4..575e9af 100644 > --- a/drivers/gpu/drm/msm/msm_atomic.c > +++ b/drivers/gpu/drm/msm/msm_atomic.c > @@ -55,16 +55,32 @@ static void vblank_put(struct msm_kms *kms, unsigned crtc_mask) > } > } > > +static void lock_crtcs(struct msm_kms *kms, unsigned int crtc_mask) > +{ > + struct drm_crtc *crtc; > + > + for_each_crtc_mask(kms->dev, crtc, crtc_mask) > + mutex_lock(&kms->commit_lock[drm_crtc_index(crtc)]); > +} > + > +static void unlock_crtcs(struct msm_kms *kms, unsigned int crtc_mask) > +{ > + struct drm_crtc *crtc; > + > + for_each_crtc_mask(kms->dev, crtc, crtc_mask) > + mutex_unlock(&kms->commit_lock[drm_crtc_index(crtc)]); > +} > + > static void msm_atomic_async_commit(struct msm_kms *kms, int crtc_idx) > { > unsigned crtc_mask = BIT(crtc_idx); > > trace_msm_atomic_async_commit_start(crtc_mask); > > - mutex_lock(&kms->commit_lock); > + lock_crtcs(kms, crtc_mask); > > if (!(kms->pending_crtc_mask & crtc_mask)) { > - mutex_unlock(&kms->commit_lock); > + unlock_crtcs(kms, crtc_mask); > goto out; > } > > @@ -79,7 +95,6 @@ static void msm_atomic_async_commit(struct msm_kms *kms, int crtc_idx) > */ > trace_msm_atomic_flush_commit(crtc_mask); > kms->funcs->flush_commit(kms, crtc_mask); > - mutex_unlock(&kms->commit_lock); > > /* > * Wait for flush to complete: > @@ -90,9 +105,8 @@ static void msm_atomic_async_commit(struct msm_kms *kms, int crtc_idx) > > vblank_put(kms, crtc_mask); > > - mutex_lock(&kms->commit_lock); > kms->funcs->complete_commit(kms, crtc_mask); > - mutex_unlock(&kms->commit_lock); > + unlock_crtcs(kms, crtc_mask); > kms->funcs->disable_commit(kms); > > out: > @@ -189,12 +203,11 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) > * Ensure any previous (potentially async) commit has > * completed: > */ > + lock_crtcs(kms, crtc_mask); > trace_msm_atomic_wait_flush_start(crtc_mask); > kms->funcs->wait_flush(kms, crtc_mask); > trace_msm_atomic_wait_flush_finish(crtc_mask); > > - mutex_lock(&kms->commit_lock); > - > /* > * Now that there is no in-progress flush, prepare the > * current update: > @@ -232,8 +245,7 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) > } > > kms->funcs->disable_commit(kms); > - mutex_unlock(&kms->commit_lock); > - > + unlock_crtcs(kms, crtc_mask); > /* > * At this point, from drm core's perspective, we > * are done with the atomic update, so we can just > @@ -260,8 +272,7 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) > */ > trace_msm_atomic_flush_commit(crtc_mask); > kms->funcs->flush_commit(kms, crtc_mask); > - mutex_unlock(&kms->commit_lock); > - > + unlock_crtcs(kms, crtc_mask); > /* > * Wait for flush to complete: > */ > @@ -271,9 +282,9 @@ void msm_atomic_commit_tail(struct drm_atomic_state *state) > > vblank_put(kms, crtc_mask); > > - mutex_lock(&kms->commit_lock); > + lock_crtcs(kms, crtc_mask); > kms->funcs->complete_commit(kms, crtc_mask); > - mutex_unlock(&kms->commit_lock); > + unlock_crtcs(kms, crtc_mask); > kms->funcs->disable_commit(kms); > > drm_atomic_helper_commit_hw_done(state); > diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h > index 1cbef6b..2049847 100644 > --- a/drivers/gpu/drm/msm/msm_kms.h > +++ b/drivers/gpu/drm/msm/msm_kms.h > @@ -155,7 +155,7 @@ struct msm_kms { > * For async commit, where ->flush_commit() and later happens > * from the crtc's pending_timer close to end of the frame: > */ > - struct mutex commit_lock; > + struct mutex commit_lock[MAX_CRTCS]; > unsigned pending_crtc_mask; > struct msm_pending_timer pending_timers[MAX_CRTCS]; > }; > @@ -165,7 +165,9 @@ static inline void msm_kms_init(struct msm_kms *kms, > { > unsigned i; > > - mutex_init(&kms->commit_lock); > + for (i = 0; i < ARRAY_SIZE(kms->commit_lock); i++) > + mutex_init(&kms->commit_lock[i]); > + > kms->funcs = funcs; > > for (i = 0; i < ARRAY_SIZE(kms->pending_timers); i++) > -- > 2.7.4 >