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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A75C9C433EF for ; Wed, 13 Apr 2022 23:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238643AbiDMXWX (ORCPT ); Wed, 13 Apr 2022 19:22:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236008AbiDMXWW (ORCPT ); Wed, 13 Apr 2022 19:22:22 -0400 Received: from mail-ot1-x32f.google.com (mail-ot1-x32f.google.com [IPv6:2607:f8b0:4864:20::32f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C64F923BCF for ; Wed, 13 Apr 2022 16:19:59 -0700 (PDT) Received: by mail-ot1-x32f.google.com with SMTP id i11-20020a9d4a8b000000b005cda3b9754aso2204583otf.12 for ; Wed, 13 Apr 2022 16:19:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:in-reply-to:references:from:user-agent:date:message-id :subject:to:cc; bh=A76+qe6l2R4PjtaHOG75B4+IXG7YG12PDKm5b7n2jWs=; b=SHoATc0eEmqjjIwRKvexraebmX2kGeRzptDhV06lGjHycAYMT+TOpWHUuC00JxUOTj RHHtsMgFG+ZIU6axzwN0FQc7X9fdSEWHjTK8L/jGvPcI/8iNhZQrE7OwFAp/5b5lWymZ ZpFMog5M4McPKnPsUbvdTa8nAmF0nFb1cEDYU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:in-reply-to:references:from :user-agent:date:message-id:subject:to:cc; bh=A76+qe6l2R4PjtaHOG75B4+IXG7YG12PDKm5b7n2jWs=; b=Ro71vUkQhtyIXBzguZaNjykA7KnHuL7zseinSGWS485QPnlgRzYFNPS53fYdCRa/9j pV9RSHSt9mWfc0MGuM0S7Vb/RsrTU6IK2gWHMYlUENp23rb2NkietY0sm8aoVJAI6lFx tGbqVHADKEHoDbeKDrxkqZH4AABKEWTQWx8Dh0JbTg6XMATi7leo3JIH+Bm7Gl6x0zhU RoOUF+A2BwXgngJEt0zpCTd8K31HRglPBr+gkLlw3n+hYX5tlGPm0RRGs6Fgevuwc1hc 57GF807H7MGuBxvKgpDOSSopioBhWA6/vtq9ouXHuFD7uLJ5Mm//F5J2Ffo06gFyjnV0 15IQ== X-Gm-Message-State: AOAM531rbhs8Ol0XnuZvvf0qZdiyPsI0+41YylEyCPMonqyM7x2+b55Y aQwO6k4QnzTlKHuLtlDs2gn5lxHccAry3YPN9iYs8w== X-Google-Smtp-Source: ABdhPJz4zQOvWO+Ka65MElptgAevAeXuKyDHAfQnJYr8K685AAWqQ2cIPgcN1VMnmhtkiEpddCxTwpmuwEtmVKjoZ5o= X-Received: by 2002:a9d:b85:0:b0:5cb:3eeb:d188 with SMTP id 5-20020a9d0b85000000b005cb3eebd188mr10346oth.77.1649891999102; Wed, 13 Apr 2022 16:19:59 -0700 (PDT) Received: from 753933720722 named unknown by gmailapi.google.com with HTTPREST; Wed, 13 Apr 2022 16:19:58 -0700 MIME-Version: 1.0 In-Reply-To: <1649883865-9012-1-git-send-email-quic_khsieh@quicinc.com> References: <1649883865-9012-1-git-send-email-quic_khsieh@quicinc.com> From: Stephen Boyd User-Agent: alot/0.10 Date: Wed, 13 Apr 2022 16:19:58 -0700 Message-ID: Subject: Re: [PATCH v2] drm/msm/dp: stop event kernel thread when DP unbind To: Kuogee Hsieh , agross@kernel.org, airlied@linux.ie, bjorn.andersson@linaro.org, daniel@ffwll.ch, dmitry.baryshkov@linaro.org, robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org Cc: quic_abhinavk@quicinc.com, quic_aravindh@quicinc.com, quic_sbillaka@quicinc.com, freedreno@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Quoting Kuogee Hsieh (2022-04-13 14:04:25) > Current DP driver implementation, event thread is kept running > after DP display is unbind. This patch fix this problem by disabling > DP irq and stop event thread to exit gracefully at dp_display_unbind(). > > Changes in v2: > -- start event thread at dp_display_bind() > > Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets") > Signed-off-by: Kuogee Hsieh > Reported-by: Dmitry Baryshkov > --- > drivers/gpu/drm/msm/dp/dp_display.c | 40 +++++++++++++++++++++++++++---------- > 1 file changed, 30 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c > index 01453db..943e4f1 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -113,6 +113,7 @@ struct dp_display_private { > u32 hpd_state; > u32 event_pndx; > u32 event_gndx; > + struct task_struct *ev_tsk; > struct dp_event event_list[DP_EVENT_Q_MAX]; > spinlock_t event_lock; > > @@ -230,6 +231,31 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display) > complete_all(&dp->audio_comp); > } > > +static int hpd_event_thread(void *data); Is there a reason why this is needed vs. defining the kthread start function after hpd_event_thread()? > + > +static void dp_hpd_event_setup(struct dp_display_private *dp_priv) Maybe dp_hpd_event_thread_start()? > +{ > + init_waitqueue_head(&dp_priv->event_q); > + spin_lock_init(&dp_priv->event_lock); > + > + dp_priv->ev_tsk = kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler"); > + > + if (IS_ERR(dp_priv->ev_tsk)) > + DRM_ERROR("failed to create DP event thread\n"); Can we return an error from this function? > +} > + > +static void dp_hpd_event_stop(struct dp_display_private *dp_priv) Maybe dp_hpd_event_thread_stop()? > +{ > + if (IS_ERR(dp_priv->ev_tsk)) > + return; If we handled the error then this check becomes impossible. > + > + kthread_stop(dp_priv->ev_tsk); > + > + /* reset event q to empty */ > + dp_priv->event_gndx = 0; > + dp_priv->event_pndx = 0; > +} > + > static int dp_display_bind(struct device *dev, struct device *master, > void *data) > { > @@ -269,6 +295,7 @@ static int dp_display_bind(struct device *dev, struct device *master, > if (rc) > DRM_ERROR("Audio registration Dp failed\n"); > > + dp_hpd_event_setup(dp); /* start event thread */ The comment is useless, please remove. > end: > return rc; > } > @@ -280,6 +307,8 @@ static void dp_display_unbind(struct device *dev, struct device *master, > struct drm_device *drm = dev_get_drvdata(master); > struct msm_drm_private *priv = drm->dev_private; > > + disable_irq(dp->irq); Is the disable_irq() necessary? It would be nicer to silence the hardware and remove the disable_irq() so that we can reason about the code assuming the irq is always enabled after it is requested. > + dp_hpd_event_stop(dp); /* stop event thread */ > dp_power_client_deinit(dp->power); > dp_aux_unregister(dp->aux); > priv->dp[dp->id] = NULL; 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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2E1C9C433F5 for ; Wed, 13 Apr 2022 23:20:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 50D2510F1E0; Wed, 13 Apr 2022 23:20:01 +0000 (UTC) Received: from mail-ot1-x331.google.com (mail-ot1-x331.google.com [IPv6:2607:f8b0:4864:20::331]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0264B10F1E0 for ; Wed, 13 Apr 2022 23:19:59 +0000 (UTC) Received: by mail-ot1-x331.google.com with SMTP id k25-20020a056830151900b005b25d8588dbso2227291otp.4 for ; Wed, 13 Apr 2022 16:19:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:in-reply-to:references:from:user-agent:date:message-id :subject:to:cc; bh=A76+qe6l2R4PjtaHOG75B4+IXG7YG12PDKm5b7n2jWs=; b=SHoATc0eEmqjjIwRKvexraebmX2kGeRzptDhV06lGjHycAYMT+TOpWHUuC00JxUOTj RHHtsMgFG+ZIU6axzwN0FQc7X9fdSEWHjTK8L/jGvPcI/8iNhZQrE7OwFAp/5b5lWymZ ZpFMog5M4McPKnPsUbvdTa8nAmF0nFb1cEDYU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:in-reply-to:references:from :user-agent:date:message-id:subject:to:cc; bh=A76+qe6l2R4PjtaHOG75B4+IXG7YG12PDKm5b7n2jWs=; b=Vx726YL92iQpKWAhi4LrAoLVGY9xgo0Jk4fbZYD9Mj9ZUs/qoxRDqS/iOsRWKWS+Mg lGz6ho9c2Ac6415Ifrwry7DklR1vESSA6HsGWgOgVyqFsH6yBlGmOKCBLa5kK7FatFHN qrBoxL9I+viP4xgg2SKt0x0abDViocXPdIHkMq4nD7T5zL4JTDORnC3Urpps6yNnjeeI OK4GF9IIB4ehBDrO/sT5JFpdnW7sl0Udg5dKMjynObaZJPOSk5ekY/H87V7o74RlhbLv 7BYPKR99zcWtbv4vXJgUuMLkIlGUvVXAiJy1ZMa4MWB7Kw2T1MmR9Q0psmYVscExPB4W dI0Q== X-Gm-Message-State: AOAM5312gZIz2mCicHa+ZwTzf1PkWCdF7VpYJy4MvT+S+LiyGSIsa11M QHPeFYq5r2tww6NiI7oZ/24/vyYW+Fcculat0VkG6Q== X-Google-Smtp-Source: ABdhPJz4zQOvWO+Ka65MElptgAevAeXuKyDHAfQnJYr8K685AAWqQ2cIPgcN1VMnmhtkiEpddCxTwpmuwEtmVKjoZ5o= X-Received: by 2002:a9d:b85:0:b0:5cb:3eeb:d188 with SMTP id 5-20020a9d0b85000000b005cb3eebd188mr10346oth.77.1649891999102; Wed, 13 Apr 2022 16:19:59 -0700 (PDT) Received: from 753933720722 named unknown by gmailapi.google.com with HTTPREST; Wed, 13 Apr 2022 16:19:58 -0700 MIME-Version: 1.0 In-Reply-To: <1649883865-9012-1-git-send-email-quic_khsieh@quicinc.com> References: <1649883865-9012-1-git-send-email-quic_khsieh@quicinc.com> From: Stephen Boyd User-Agent: alot/0.10 Date: Wed, 13 Apr 2022 16:19:58 -0700 Message-ID: Subject: Re: [PATCH v2] drm/msm/dp: stop event kernel thread when DP unbind To: Kuogee Hsieh , agross@kernel.org, airlied@linux.ie, bjorn.andersson@linaro.org, daniel@ffwll.ch, dmitry.baryshkov@linaro.org, robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: quic_sbillaka@quicinc.com, linux-arm-msm@vger.kernel.org, quic_abhinavk@quicinc.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, quic_aravindh@quicinc.com, freedreno@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Quoting Kuogee Hsieh (2022-04-13 14:04:25) > Current DP driver implementation, event thread is kept running > after DP display is unbind. This patch fix this problem by disabling > DP irq and stop event thread to exit gracefully at dp_display_unbind(). > > Changes in v2: > -- start event thread at dp_display_bind() > > Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets") > Signed-off-by: Kuogee Hsieh > Reported-by: Dmitry Baryshkov > --- > drivers/gpu/drm/msm/dp/dp_display.c | 40 +++++++++++++++++++++++++++---------- > 1 file changed, 30 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c > index 01453db..943e4f1 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -113,6 +113,7 @@ struct dp_display_private { > u32 hpd_state; > u32 event_pndx; > u32 event_gndx; > + struct task_struct *ev_tsk; > struct dp_event event_list[DP_EVENT_Q_MAX]; > spinlock_t event_lock; > > @@ -230,6 +231,31 @@ void dp_display_signal_audio_complete(struct msm_dp *dp_display) > complete_all(&dp->audio_comp); > } > > +static int hpd_event_thread(void *data); Is there a reason why this is needed vs. defining the kthread start function after hpd_event_thread()? > + > +static void dp_hpd_event_setup(struct dp_display_private *dp_priv) Maybe dp_hpd_event_thread_start()? > +{ > + init_waitqueue_head(&dp_priv->event_q); > + spin_lock_init(&dp_priv->event_lock); > + > + dp_priv->ev_tsk = kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler"); > + > + if (IS_ERR(dp_priv->ev_tsk)) > + DRM_ERROR("failed to create DP event thread\n"); Can we return an error from this function? > +} > + > +static void dp_hpd_event_stop(struct dp_display_private *dp_priv) Maybe dp_hpd_event_thread_stop()? > +{ > + if (IS_ERR(dp_priv->ev_tsk)) > + return; If we handled the error then this check becomes impossible. > + > + kthread_stop(dp_priv->ev_tsk); > + > + /* reset event q to empty */ > + dp_priv->event_gndx = 0; > + dp_priv->event_pndx = 0; > +} > + > static int dp_display_bind(struct device *dev, struct device *master, > void *data) > { > @@ -269,6 +295,7 @@ static int dp_display_bind(struct device *dev, struct device *master, > if (rc) > DRM_ERROR("Audio registration Dp failed\n"); > > + dp_hpd_event_setup(dp); /* start event thread */ The comment is useless, please remove. > end: > return rc; > } > @@ -280,6 +307,8 @@ static void dp_display_unbind(struct device *dev, struct device *master, > struct drm_device *drm = dev_get_drvdata(master); > struct msm_drm_private *priv = drm->dev_private; > > + disable_irq(dp->irq); Is the disable_irq() necessary? It would be nicer to silence the hardware and remove the disable_irq() so that we can reason about the code assuming the irq is always enabled after it is requested. > + dp_hpd_event_stop(dp); /* stop event thread */ > dp_power_client_deinit(dp->power); > dp_aux_unregister(dp->aux); > priv->dp[dp->id] = NULL;