From patchwork Fri Oct 16 14:10:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krishna Manikandan X-Patchwork-Id: 11841773 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD08C1752 for ; Fri, 16 Oct 2020 14:11:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC4B821D40 for ; Fri, 16 Oct 2020 14:11:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408595AbgJPOLM (ORCPT ); Fri, 16 Oct 2020 10:11:12 -0400 Received: from alexa-out.qualcomm.com ([129.46.98.28]:56738 "EHLO alexa-out.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2408593AbgJPOLL (ORCPT ); Fri, 16 Oct 2020 10:11:11 -0400 Received: from ironmsg08-lv.qualcomm.com ([10.47.202.152]) by alexa-out.qualcomm.com with ESMTP; 16 Oct 2020 07:11:09 -0700 X-QCInternal: smtphost Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg08-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 16 Oct 2020 07:11:07 -0700 X-QCInternal: smtphost Received: from mkrishn-linux.qualcomm.com ([10.204.66.35]) by ironmsg02-blr.qualcomm.com with ESMTP; 16 Oct 2020 19:40:47 +0530 Received: by mkrishn-linux.qualcomm.com (Postfix, from userid 438394) id F2461213ED; Fri, 16 Oct 2020 19:40:45 +0530 (IST) From: Krishna Manikandan To: dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, devicetree@vger.kernel.org Cc: Krishna Manikandan , linux-kernel@vger.kernel.org, robdclark@gmail.com, seanpaul@chromium.org, hoegsberg@chromium.org, kalyan_t@codeaurora.org, dianders@chromium.org Subject: [v3] drm/msm: Fix race condition in msm driver with async layer updates Date: Fri, 16 Oct 2020 19:40:43 +0530 Message-Id: <1602857443-27317-1-git-send-email-mkrishn@codeaurora.org> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org 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++)