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 56CC3C6FA83 for ; Mon, 12 Sep 2022 19:26:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230121AbiILT0W (ORCPT ); Mon, 12 Sep 2022 15:26:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229677AbiILT0U (ORCPT ); Mon, 12 Sep 2022 15:26:20 -0400 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89D4C43E7F; Mon, 12 Sep 2022 12:26:19 -0700 (PDT) Received: from pps.filterd (m0279863.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28CFkXrJ032110; Mon, 12 Sep 2022 19:26:05 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=rkNjMNHOv/NYMM/1RaZBcC4DunJrDyumUuvelfbNDUo=; b=gCYr3NZP7mPs0JwUmRZMSyy/bJOtb4CaIUf5/CPZywNWnqMOJpIno75gazkokHjoP50l X/RboO2ZHBSnCETxHVOzRzapw7FIxpPYsrTlNw7/R2PQc/eI/WtXOVNRAPHd3Wwgb8af iI2trXIls/di9FjMvnAKlacwTN8fmHjZZyFTFIsLF52hcTEJgk8x0Bo2l5XP/meV/sSq IkpKE18I8dO/TqacDtPqVFLPkPT825nGiGT60gFQ045u85adylKcvVHC2qnf4IIBPMUE FrpeyUFaq+sqMvtNhLE8BCqZjhE1k1RSFsc7bXzWXuyXnvj3su1vcgg4uwBC6wTftMCY Tg== Received: from nalasppmta05.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3jgk43p574-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 12 Sep 2022 19:26:05 +0000 Received: from nalasex01a.na.qualcomm.com (nalasex01a.na.qualcomm.com [10.47.209.196]) by NALASPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 28CJQ4rC017147 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 12 Sep 2022 19:26:04 GMT Received: from [10.110.24.172] (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 15.2.986.29; Mon, 12 Sep 2022 12:26:03 -0700 Message-ID: <61d591ff-c5d8-a032-9eaa-6ab4c535a679@quicinc.com> Date: Mon, 12 Sep 2022 12:26:03 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH v5 3/3] drm/msm/dp: retry 3 times if set sink to D0 poweer state failed Content-Language: en-US To: Dmitry Baryshkov , , , , , , , , , , CC: , , , , References: <1662999830-13916-1-git-send-email-quic_khsieh@quicinc.com> <1662999830-13916-4-git-send-email-quic_khsieh@quicinc.com> <067c7bc0-4746-f714-db56-a3c9e4f25588@linaro.org> From: Kuogee Hsieh In-Reply-To: <067c7bc0-4746-f714-db56-a3c9e4f25588@linaro.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] 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: 9nVmejWZCrRQ_evv2KlVzd7WHkceDug0 X-Proofpoint-ORIG-GUID: 9nVmejWZCrRQ_evv2KlVzd7WHkceDug0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-12_13,2022-09-12_02,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 clxscore=1015 mlxscore=0 priorityscore=1501 impostorscore=0 phishscore=0 bulkscore=0 malwarescore=0 adultscore=0 spamscore=0 suspectscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000 definitions=main-2209120065 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/12/2022 11:37 AM, Dmitry Baryshkov wrote: > On 12/09/2022 19:23, Kuogee Hsieh wrote: >> Bring sink out of D3 (power down) mode into D0 (normal operation) mode >> by setting DP_SET_POWER_D0 bit to DP_SET_POWER dpcd register. This >> patch will retry 3 times if written to DP_SET_POWER register failed. > > Could you please elaborate this change? Can the sink succeed in > reading the DP_SET_POWER, but fail writing DP_SET_POWER? yes, there is possible since it is not only set local sink device but also all downstream sink devices to D0 state. > >> >> Changes in v5: >> -- split into two patches >> >> Signed-off-by: Kuogee Hsieh >> --- >>   drivers/gpu/drm/msm/dp/dp_link.c | 13 ++++++++----- >>   1 file changed, 8 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/dp/dp_link.c >> b/drivers/gpu/drm/msm/dp/dp_link.c >> index 9d5381d..4360728 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_link.c >> +++ b/drivers/gpu/drm/msm/dp/dp_link.c >> @@ -50,6 +50,7 @@ static int dp_aux_link_power_up(struct drm_dp_aux >> *aux, >>   { >>       u8 value; >>       ssize_t len; >> +    int i; >>         if (link->revision < 0x11) >>           return 0; >> @@ -61,11 +62,13 @@ static int dp_aux_link_power_up(struct drm_dp_aux >> *aux, >>       value &= ~DP_SET_POWER_MASK; >>       value |= DP_SET_POWER_D0; >>   -    len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >> -    if (len < 0) >> -        return len; >> - >> -    usleep_range(1000, 2000); >> +    /* retry for 1ms to give the sink time to wake up */ >> +    for (i = 0; i < 3; i++) { >> +        len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value); >> +        usleep_range(1000, 2000); >> +        if (len == 1) >> +            break; >> +    } >>         return 0; >>   } >