From patchwork Wed Dec 28 02:16:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuogee Hsieh X-Patchwork-Id: 13082697 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 016F9C46467 for ; Wed, 28 Dec 2022 02:16:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232412AbiL1CQn (ORCPT ); Tue, 27 Dec 2022 21:16:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230001AbiL1CQm (ORCPT ); Tue, 27 Dec 2022 21:16:42 -0500 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F34CE1B7; Tue, 27 Dec 2022 18:16:41 -0800 (PST) Received: from pps.filterd (m0279867.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2BS2F32H004143; Wed, 28 Dec 2022 02:16:36 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=qcppdkim1; bh=MErpBrBhqspvh5y6LZ64TOzF9sRK2Tglmn2Zo9OAXWk=; b=RT3sOeb04pc5mobHf9H1A01j3UNTUBw6SQHoooBslJJCSpp54yysdRcu2Ai+EJV0gniQ M2+mHoC976bNR9kA4udShZHIlCnMRluzg9kPvMxljy5P87E0On9k4BkbnLZhlX8hmG3S QE5z+sKxmEV+Tc/1dzjb7iheQwc6jMVfPcbwhWQfTlsYY1zCag6w4QvrP7I2gnMC4iMs qtZ1tj4JDjIwfpXnPcePfVRkErYWh2OTqJ7p23rIp/62WiGqL2PiQsFf6h3SabPsWLTA 8Zq9oiAWDEPN6ACvfPaI2Hx07PpSynl6TW8Qm90BeLlYbkBQ67dVWPHCMsEyN8KkSFKa rg== Received: from nalasppmta02.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3mnq4qx02u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Dec 2022 02:16:36 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA02.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 2BS2GZuT023819 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Dec 2022 02:16:35 GMT Received: from khsieh-linux1.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 15.2.986.36; Tue, 27 Dec 2022 18:16:34 -0800 From: Kuogee Hsieh To: , , , , , , , , , , CC: Kuogee Hsieh , , , , , Subject: [PATCH v6 1/2] drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer Date: Tue, 27 Dec 2022 18:16:24 -0800 Message-ID: <1672193785-11003-2-git-send-email-quic_khsieh@quicinc.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1672193785-11003-1-git-send-email-quic_khsieh@quicinc.com> References: <1672193785-11003-1-git-send-email-quic_khsieh@quicinc.com> MIME-Version: 1.0 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) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: Xl5Y8eX9Fxo0xMknTBDQ0dzvOwKbyRsm X-Proofpoint-ORIG-GUID: Xl5Y8eX9Fxo0xMknTBDQ0dzvOwKbyRsm X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-27_18,2022-12-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 mlxscore=0 phishscore=0 impostorscore=0 bulkscore=0 malwarescore=0 clxscore=1015 priorityscore=1501 mlxlogscore=770 adultscore=0 spamscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2212280015 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org There are 3 possible interrupt sources are handled by DP controller, HPDstatus, Controller state changes and Aux read/write transaction. At every irq, DP controller have to check isr status of every interrupt sources and service the interrupt if its isr status bits shows interrupts are pending. There is potential race condition may happen at current aux isr handler implementation since it is always complete dp_aux_cmd_fifo_tx() even irq is not for aux read or write transaction. This may cause aux read transaction return premature if host aux data read is in the middle of waiting for sink to complete transferring data to host while irq happen. This will cause host's receiving buffer contains unexpected data. This patch fixes this problem by checking aux isr and return immediately at aux isr handler if there are no any isr status bits set. Current there is a bug report regrading eDP edid corruption happen during system booting up. After lengthy debugging to found that VIDEO_READY interrupt was continuously firing during system booting up which cause dp_aux_isr() to complete dp_aux_cmd_fifo_tx() prematurely to retrieve data from aux hardware buffer which is not yet contains complete data transfer from sink. This cause edid corruption. Follows are the signature at kernel logs when problem happen, EDID has corrupt header panel-simple-dp-aux aux-aea0000.edp: Couldn't identify panel via EDID Changes in v2: -- do complete if (ret == IRQ_HANDLED) ay dp-aux_isr() -- add more commit text Changes in v3: -- add Stephen suggested -- dp_aux_isr() return IRQ_XXX back to caller -- dp_ctrl_isr() return IRQ_XXX back to caller Changes in v4: -- split into two patches Changes in v5: -- delete empty line between tags Changes in v6: -- remove extra "that" and fixed line more than 75 char at commit text Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Kuogee Hsieh Tested-by: Douglas Anderson Reviewed-by: Abhinav Kumar Reviewed-by: Dmitry Baryshkov --- drivers/gpu/drm/msm/dp/dp_aux.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c index d030a93..cc3efed 100644 --- a/drivers/gpu/drm/msm/dp/dp_aux.c +++ b/drivers/gpu/drm/msm/dp/dp_aux.c @@ -423,6 +423,10 @@ void dp_aux_isr(struct drm_dp_aux *dp_aux) isr = dp_catalog_aux_get_irq(aux->catalog); + /* no interrupts pending, return immediately */ + if (!isr) + return; + if (!aux->cmd_busy) return;