From nobody Mon Feb 9 09:00:01 2026 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E957363; Sat, 6 Apr 2024 00:17:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712362658; cv=none; b=jRskRNNCHRTesjtMVwoSnxUREiYjRSF2Pv9nUkNefGQMrBRjT9TwQkZ1GbJMTt1L6XvGvpFPnlbVWDKCp7I/Db/MeO0MUgOB7IX7vVGNMMKEDyggALnIfpkwjE7YFp59hY1D0MfWBdZd/yf9FpAdw781HL0ZTApoCEIGR6p5LTk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712362658; c=relaxed/simple; bh=BTulhtY/9Oy572CYjZLRFkgUKDeK+wOMHOC+bJntT4Y=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=UgoC1C4U1gOeWQ28z4Fdk2YFdqbrSb1beaujU3dbLTEHglpDHc8eGc79PdrZDzKyqGy/kcB/hBVvp1noBzB5qv+SLHKYjrLiijuUS81SX8/eOkRSEHIEzQ9uQQk9BFTKJK9bnSnDY0sDmmsaqyr8WpKqEmUb/bTZga+mTidiRMM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=auLtYgNM; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="auLtYgNM" Received: from pps.filterd (m0279873.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.24/8.17.1.24) with ESMTP id 435NouIN020781; Sat, 6 Apr 2024 00:17:26 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding:content-type; s=qcppdkim1; bh=PcooOqL N8RXngIbQhg9Z61r/5fHlOoN76fVOjQMWr3Y=; b=auLtYgNMAysPBT9X/DiTO15 Q7WXK4DC0s7MFmBfcqmSVJ1h00CNKk6hhkxGspVXm2RKwHK16iiBrmdZtqE5DY7T I9v/5P7tDskN5hoZWLEVA9/7n9hLtQDSu+zeSxoEl1TPCnajexfZLbEo/8HSSPjX DOhyGfXxkB/B/8AFPlcQ10/Wbcc+fg19qFev79cOQ5Z+IsVzkEFIZqCJo5AOIREz gO4PCxAZcmYYWWLy7DpOf2+6rQBvAkITpk5Yk0UrGc6oCN+HHurFBqS1Z9nY3UMh P0umQSssWxge69NXlHf7Iuy3gKICcBOd3WxdUVkwZawEphLKS+RUnLASYEJNzxQ= = Received: from nalasppmta04.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3xa8fc2f9s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 06 Apr 2024 00:17:25 +0000 (GMT) Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 4360HOMf024602 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 6 Apr 2024 00:17:24 GMT Received: from jesszhan-linux.qualcomm.com (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 15.2.1544.4; Fri, 5 Apr 2024 17:17:23 -0700 From: Abhinav Kumar To: , Rob Clark , Abhinav Kumar , Dmitry Baryshkov , Sean Paul , Marijn Suijten , David Airlie , "Daniel Vetter" , Bjorn Andersson , "Kuogee Hsieh" CC: , , , , , , , Subject: [PATCH v2] drm/msm/dp: call dp_hpd_plug_handle()/unplug_handle() directly for external HPD Date: Fri, 5 Apr 2024 17:17:14 -0700 Message-ID: <20240406001715.8181-1-quic_abhinavk@quicinc.com> X-Mailer: git-send-email 2.43.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01a.na.qualcomm.com (10.47.209.196) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: c6CjJTsfoP7elp0HjNKekg1Y4Lb4eZf1 X-Proofpoint-ORIG-GUID: c6CjJTsfoP7elp0HjNKekg1Y4Lb4eZf1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1011,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-04-05_29,2024-04-05_02,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxscore=0 malwarescore=0 mlxlogscore=999 bulkscore=0 suspectscore=0 clxscore=1011 priorityscore=1501 adultscore=0 phishscore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2404010003 definitions=main-2404060000 Content-Type: text/plain; charset="utf-8" From: Kuogee Hsieh In the external HPD case, hotplug event is delivered by pmic glink to DP dr= iver using drm_aux_hpd_bridge_notify(). The stacktrace showing the sequence of events is below: dp_bridge_hpd_notify+0x18/0x70 [msm] drm_bridge_connector_detect+0x60/0xe8 [drm_kms_helper] drm_helper_probe_detect+0x94/0xc0 [drm_kms_helper] drm_helper_probe_single_connector_modes+0x43c/0x53c [drm_kms_helper] drm_client_modeset_probe+0x240/0x1114 [drm] drm_fb_helper_hotplug_event.part.26+0x9c/0xe8 [drm_kms_helper] drm_fb_helper_hotplug_event+0x24/0x38 [drm_kms_helper] msm_fbdev_client_hotplug+0x24/0xd4 [msm] drm_client_dev_hotplug+0xd8/0x148 [drm] drm_kms_helper_connector_hotplug_event+0x30/0x3c [drm_kms_helper] drm_bridge_connector_handle_hpd+0x84/0x94 [drm_kms_helper] drm_bridge_connector_hpd_cb+0xc/0x14 [drm_kms_helper] drm_bridge_hpd_notify+0x38/0x50 [drm] drm_aux_hpd_bridge_notify+0x14/0x20 [aux_hpd_bridge] pmic_glink_altmode_worker+0xec/0x27c [pmic_glink_altmode] process_scheduled_works+0x17c/0x2cc worker_thread+0x2ac/0x2d0 kthread+0xfc/0x120 There are three notifications delivered to DP driver for each notification = event. 1) From the drm_aux_hpd_bridge_notify() itself as shown above 2) From output_poll_execute() thread which arises due to drm_helper_probe_single_connector_modes() call of the above stacktrace as shown in more detail here. dp_bridge_hpd_notify+0x18/0x70 [msm] drm_bridge_connector_detect+0x60/0xe8 [drm_kms_helper] drm_helper_probe_detect+0x94/0xc0 [drm_kms_helper] drm_helper_probe_single_connector_modes+0x43c/0x53c [drm_kms_helper] drm_client_modeset_probe+0x240/0x1114 [drm] drm_fb_helper_hotplug_event.part.26+0x9c/0xe8 [drm_kms_helper] drm_fb_helper_hotplug_event+0x24/0x38 [drm_kms_helper] msm_fbdev_client_hotplug+0x24/0xd4 [msm] drm_client_dev_hotplug+0xd8/0x148 [drm] drm_kms_helper_hotplug_event+0x30/0x3c [drm_kms_helper] output_poll_execute+0xe0/0x210 [drm_kms_helper] 3) From the DP driver as the dp_bridge_hpd_notify() callback today triggers the hpd_event_thread for connect and disconnect events respectively via bel= ow stack dp_bridge_hpd_notify+0x18/0x70 [msm] drm_bridge_connector_detect+0x60/0xe8 [drm_kms_helper] drm_helper_probe_detect_ctx+0x98/0x110 [drm_kms_helper] check_connector_changed+0x4c/0x20c [drm_kms_helper] drm_helper_hpd_irq_event+0x98/0x120 [drm_kms_helper] hpd_event_thread+0x478/0x5bc [msm] We have to address why we end up with 3 events for every single event so so= mething is broken with how we work with the drm_bridge_connector. But, the dp_bridge_hpd_notify() delivered from output_poll_execute() thread= will return the incorrect HPD status DP driver because the .detect() returns the= value of link_ready and not the HPD status currently. And because the HPD event thread has not run yet and this results in the tw= o complementary events. To fix this problem lets have dp_bridge_hpd_notify() call dp_hpd_plug_handle/unplug_handle() directly instead of going through the event thread. Then the following .detect() called by drm_kms_helper_connector_hotplug_eve= nt() will return correct value of HPD status since it uses the correct link_read= y value. With this change, the HPD status delivered by both drm_bridge_connector_hpd= _notify() and drm_kms_helper_connector_hotplug_event() will match each other consiste= ntly. changes in v2: - Fix the commit message to explain the scenario - Fix the subject a little as well Fixes: 542b37efc20e ("drm/msm/dp: Implement hpd_notify()") Signed-off-by: Kuogee Hsieh Signed-off-by: Abhinav Kumar --- drivers/gpu/drm/msm/dp/dp_display.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/d= p_display.c index d80f89581760..dfb10584ff97 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -1665,7 +1665,8 @@ void dp_bridge_hpd_notify(struct drm_bridge *bridge, return; =20 if (!dp_display->link_ready && status =3D=3D connector_status_connected) - dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0); + dp_hpd_plug_handle(dp, 0); else if (dp_display->link_ready && status =3D=3D connector_status_disconn= ected) - dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0); + dp_hpd_unplug_handle(dp, 0); + } --=20 2.43.2