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 0D1A5C433F5 for ; Tue, 12 Apr 2022 00:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241374AbiDLAcC (ORCPT ); Mon, 11 Apr 2022 20:32:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229874AbiDLAcA (ORCPT ); Mon, 11 Apr 2022 20:32:00 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3173223BD5; Mon, 11 Apr 2022 17:29:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1649723384; x=1681259384; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=sTXpV5DW8lvf+IzZXjWtfGRdgfLj3MQBE9SGJw2TAZQ=; b=Y/yrn0LLSx6CsqCRCOeF8pBJokYmVJA1Gi0LGH8d4oA1fchN877dnoP0 5Zptp/aUBnfuniTp+dSF/MO1XN/xf0prdP0HPvfbjcDrBylOaNq/fkL/n HIT+wcBzLPND6XGSLa4sZmQosblV1qWkcfTMyN5QxKQ0rKNMFL1TloR5S E=; Received: from ironmsg07-lv.qualcomm.com ([10.47.202.151]) by alexa-out.qualcomm.com with ESMTP; 11 Apr 2022 17:29:44 -0700 X-QCInternal: smtphost Received: from nasanex01c.na.qualcomm.com ([10.47.97.222]) by ironmsg07-lv.qualcomm.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Apr 2022 17:29:43 -0700 Received: from nalasex01a.na.qualcomm.com (10.47.209.196) by nasanex01c.na.qualcomm.com (10.47.97.222) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Mon, 11 Apr 2022 17:29:22 -0700 Received: from [10.111.166.27] (10.80.80.8) by nalasex01a.na.qualcomm.com (10.47.209.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.22; Mon, 11 Apr 2022 17:29:19 -0700 Message-ID: Date: Mon, 11 Apr 2022 17:29:17 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.6.2 Subject: Re: [PATCH] drm/msm/dp: stop event kernel thread when DP unbind Content-Language: en-US To: Dmitry Baryshkov , Stephen Boyd , Kuogee Hsieh , , , , , , , CC: , , , , , References: <1649722129-12542-1-git-send-email-quic_khsieh@quicinc.com> <7529d921-0b12-d162-416d-3542933a0aed@linaro.org> From: Abhinav Kumar In-Reply-To: <7529d921-0b12-d162-416d-3542933a0aed@linaro.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01a.na.qualcomm.com (10.47.209.196) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/11/2022 5:22 PM, Dmitry Baryshkov wrote: > On 12/04/2022 03:21, Stephen Boyd wrote: >> Quoting Kuogee Hsieh (2022-04-11 17:08:49) >>> 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(). >>> >>> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on >>> Snapdragon Chipsets") >>> Signed-off-by: Kuogee Hsieh >> >> Should add a Reported-by tag from Dmitry here. >> >>> --- >>>   drivers/gpu/drm/msm/dp/dp_display.c | 24 ++++++++++++++++++++++-- >>>   1 file changed, 22 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c >>> b/drivers/gpu/drm/msm/dp/dp_display.c >>> index 01453db..fa1ef8e 100644 >>> --- a/drivers/gpu/drm/msm/dp/dp_display.c >>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c >>> @@ -273,6 +274,8 @@ static int dp_display_bind(struct device *dev, >>> struct device *master, >>>          return rc; >>>   } >>> >>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv); >> >> Why can't the function be defined here? >> >>> + >>>   static void dp_display_unbind(struct device *dev, struct device >>> *master, >>>                                void *data) >>>   { >>> @@ -280,6 +283,8 @@ 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); >>> +       dp_hpd_event_stop(dp); >>>          dp_power_client_deinit(dp->power); >>>          dp_aux_unregister(dp->aux); >>>          priv->dp[dp->id] = NULL; >>> @@ -1054,7 +1059,7 @@ static int hpd_event_thread(void *data) >>> >>>          dp_priv = (struct dp_display_private *)data; >>> >>> -       while (1) { >>> +       while (!kthread_should_stop()) { >>>                  if (timeout_mode) { >>>                          wait_event_timeout(dp_priv->event_q, >>>                                  (dp_priv->event_pndx == >>> dp_priv->event_gndx), >>> @@ -1137,7 +1142,22 @@ static void dp_hpd_event_setup(struct >>> dp_display_private *dp_priv) >>>          init_waitqueue_head(&dp_priv->event_q); >>>          spin_lock_init(&dp_priv->event_lock); >>> >>> -       kthread_run(hpd_event_thread, dp_priv, "dp_hpd_handler"); >>> +       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"); >> >> Why can't we error out? Why can't this kthread be started in probe? > > Just my 2c. I don't think starting it in probe is a good idea. The > driver uses components, so, in my opinion, the thread should be started > from bind and stopped in unbind. Yes, I also agree it should be started in bind and stopped in unbind. > >> >>> +} >>> + >>> +static void dp_hpd_event_stop(struct dp_display_private *dp_priv) >>> +{ >>> +       if (IS_ERR(dp_priv->ev_tsk)) >>> +               return; >>> + >>> +       kthread_stop(dp_priv->ev_tsk); >>> + >>> +       /* reset event q to empty */ >>> +       dp_priv->event_gndx = 0; >>> +       dp_priv->event_pndx = 0; >>>   } >>> > >