From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) (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 882751E9B37 for ; Tue, 4 Nov 2025 16:38:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.168.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762274327; cv=none; b=RCoRaAeXrnja5ps/0fx2zdUnNUFMb96QTbEhrZmsj8h3Xn6aW8x7TvJRPCaFv5QA3wSTCDcDQR7uciVBzql0QPoZDv0TQNp6GuqeX8ZVFCAKEUx4gYmyVg7dBMIlfpq5yexCqJFkVyJE2VQvAGPLJV4Z9fq6+0A9q2AZsrPlgFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762274327; c=relaxed/simple; bh=WP9gc6aoabGI8uiHDARaHICukxcNlD501b4UKexOpVc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=a+VS7M0RUYdfVuq2XR+3Sde/aC4rjDk+SoPsjdQBCthaKcRJnh/L1o5WhlPfLTQXGKuGyeLrt8kKXEAwsVkTXSaFIoHR6rVm/ifTfbOWXwrwTAy76WWEtytUiAXHpxz0dOw5vTpL1OKD7X7Y0OtLWOddjEFLKVw1Stt/pjlOmM4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b=i+MZG+D9; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=SJ/ro4sE; arc=none smtp.client-ip=205.220.168.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=qualcomm.com header.i=@qualcomm.com header.b="i+MZG+D9"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="SJ/ro4sE" Received: from pps.filterd (m0279864.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 5A4FecJ92284756 for ; Tue, 4 Nov 2025 16:38:45 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= WP9gc6aoabGI8uiHDARaHICukxcNlD501b4UKexOpVc=; b=i+MZG+D9QijvQiYs E5oTiPE4X7OJCHpTaXS8W6BbOL9JuFfBzOSGrV2EXRABaM22NisFXwPEN5KJI0xF EI12SU2ybN7gCw/QqXjRaZ8PoTKD1Uc2nNt50nbhn6nwPwWxIaGUfRTKzHIXjO4b /vRJr5oTbNd15FiAOl7e+DdUe9HaMNoeOl5J9ec9XOf2iAH27ny9OcYtLayrqno5 OAt/XXaWJHJDfqAcOW0UWlLG882Io6b2C3UGWVrtlUBsCOLmQ9RnJpO6y7yD2tWo x4UuvD+Jsrrc8zP/0tLA8fcUKVwUEZJjAQIITOqsZnLz3Udrmy0ikMr/T5Z1T3UZ QVuu8Q== Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4a7mbbr680-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Tue, 04 Nov 2025 16:38:45 +0000 (GMT) Received: by mail-pl1-f197.google.com with SMTP id d9443c01a7336-295915934bfso40597715ad.0 for ; Tue, 04 Nov 2025 08:38:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1762274325; x=1762879125; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=WP9gc6aoabGI8uiHDARaHICukxcNlD501b4UKexOpVc=; b=SJ/ro4sEwYIQXCEJTaNHZy7nrFSWgXneNxXPfnzkN5KzhwQgclVLVOLJ0uZ1RnbP1T qDs6bJxcj2BN5zApJ1+AZY51nvvcP7nJhBIz/BMumdkHKxZPQD6SL/XIIvNEAkYkERPa jMEh32eT4mjd+Es9TTcZ16CeUKIc//QbluxyU0ZFbsH5gdmH8y99qknRTlxdsOyZTDOP zzWcagl9y/bkdwZ9nOBvVWF5efX4ex9rFkPL8yLMJj4zNX2M/i297qULkSRYq2X6szFx ADoZmwCKkjtze+RNZsvQjaHJIwL1dyvff2lkZ4Xq8VgZiaBjMEdiMQsjyMiCNCWmvXU4 WazQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762274325; x=1762879125; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WP9gc6aoabGI8uiHDARaHICukxcNlD501b4UKexOpVc=; b=o3p4DLeUXSGm34lhdu+GCRtgVAJylCqe5WDAu0HNNOCboZdoB6FJcA1dFjEoO0VjQ2 j0KVCbz/5aMs/4gV6jbRqKC1E5UZA7QMWYt+nWxFc1JJcM3OXOdKm3SWqblBGyxJ8o+F rWgRSIJYYEFrGWhW87aS8ObVAJnmfirXwQR6U1w6HCTmqec/Mbpk+e/7Yj12D4JEPzAL kDTLGp/A9A5bfne8g8RavwB+uh34zQyeL+ZnmxdZRt10wS8djRUJcbfCPPPtFdG04J+E zPG1XpA+arfsY68WTQ1K4lTIZNB3mjMvadMLjjGb6IhYecBP5IOGCi+kc885EJp4Chgv NCBg== X-Forwarded-Encrypted: i=1; AJvYcCVwCum510hiUesu08tto/GXQvGVa3+bm2YXyba9qyU+ykUH/DkiYDzP6Td+dfNb0qLG2Ovlv3bslpfr2m7d@vger.kernel.org X-Gm-Message-State: AOJu0YwD6lhHg2UXtPmVYrjdAr8xS+I3AVnj96upO1pxe8xf31Jh03eJ rcj4YdO+kaN7PFLoVMDJ2Cmlk996cqGzwZmp6qVewhQqIioXnTlK1kWex77VmHyNuRINQdiGobQ sGz8+aoGSSLSseNIgNVgAsWhhGiek0bSL1QnA9laKPQS893DD/Y4KNoeEc5OEyk/e4cbu X-Gm-Gg: ASbGncvOxVEz6UckhQ0JGzOjtmYZc6+sLxwyhv3mt5IVibQnkW0szKy+8HASN1KI60J RkWi3vXgrhsBd/iKEoB9n3LCpIG8Hps37WVjcQ2UF3k1kKhaEK0DXTpQKykAi3VK8e5Ih7VaTwP Ky4cVYWUqROPwtxXo8+EIPcpPVt0vRHlW68yjrgf+Y9abCpzoAzxolR86xIRqmIbwN8YbShN1gX 0tuqdUmCo7GUvNTfQDnPu89pLpxIKz2ldqrrBwRnckTwh8pDp08E6Dp1U/3cWsni2ZKqLAIoX2Z RsedmLTGhKRfAYNkPg8ehZXTnQA+4m42LbdoUvgkvlQ4yTQ7AjlSCl1n+I1Ypx6IhPZH6di05gK oiDE76yJ8Y738xPrRA6c1/7K59RDEob9oUg== X-Received: by 2002:a17:903:46c6:b0:295:39d9:8971 with SMTP id d9443c01a7336-2962ad0c936mr3416785ad.1.1762274324896; Tue, 04 Nov 2025 08:38:44 -0800 (PST) X-Google-Smtp-Source: AGHT+IGz6uJF0hcsIaWD0Bqp9R29GTarddruadQBQ56H22/WdcYPRdszrtsBx7nayDpricbv68SMYA== X-Received: by 2002:a17:903:46c6:b0:295:39d9:8971 with SMTP id d9443c01a7336-2962ad0c936mr3416255ad.1.1762274324314; Tue, 04 Nov 2025 08:38:44 -0800 (PST) Received: from [192.168.29.63] ([49.43.227.162]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29601972a9fsm31883835ad.20.2025.11.04.08.38.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Nov 2025 08:38:44 -0800 (PST) Message-ID: <2d4a192f-45b2-4aee-bcc9-dbe0dce0aa93@oss.qualcomm.com> Date: Tue, 4 Nov 2025 22:08:35 +0530 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] PCI: qcom: Program correct T_POWER_ON value for L1.2 exit timing To: Konrad Dybcio , Manivannan Sadhasivam , Lorenzo Pieralisi , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, mayank.rana@oss.qualcomm.com, quic_vbadigan@quicinc.com References: <20251104-t_power_on_fux-v1-1-eb5916e47fd7@oss.qualcomm.com> <29b32098-39ca-440d-9b51-915157b752b5@oss.qualcomm.com> Content-Language: en-US From: Krishna Chaitanya Chundru In-Reply-To: <29b32098-39ca-440d-9b51-915157b752b5@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-ORIG-GUID: ut08ioytUY_AMxFHO1ismL_w1TZx75jl X-Proofpoint-GUID: ut08ioytUY_AMxFHO1ismL_w1TZx75jl X-Authority-Analysis: v=2.4 cv=MK1tWcZl c=1 sm=1 tr=0 ts=690a2c15 cx=c_pps a=cmESyDAEBpBGqyK7t0alAg==:117 a=ISmZZG41GQzdpg15mxjwIw==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=WGPAbWhItJlpQzQmOdIA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=1OuFwYUASf3TG4hYMiVC:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA0MDEzOSBTYWx0ZWRfX1S5xITPxN0BI GQNsNVukqmoiW8X4TlfRhkZOylc+i4J6rYm06GJVn6J0DAcnV/wrJLnNDUMS0hO3Li2p8iR9CrS XY/r1m4PpI2xSIB5L6+/rAWsDrcnVRdOm9wJzX575LyeWdAs0i7dmjHc/b8BBLucaIARLhRYpp/ M2eQY76r/SFSw6/4rZWKok62HsQMti7ta9hpiNskgz/jYVNfcf4ji7sokipigtma+d9yr63DsiG gJHgSRDJKl9+ETp3npcVYHTB5flvfjYP4U9KQn78Db59hOiAEYoocSh/X0TMApCjizk6dx+9C+n GnnbSfWdfAPFRtGK94DZ3y8k7lGyIN7/ThJcYAZn2biTWlq9TmfndblOxwQp5rajfEyMgamFlDg 0FOf2SSKJ/CizY+xKy5UNpz4sR89Bg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-04_02,2025-11-03_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 phishscore=0 priorityscore=1501 lowpriorityscore=0 adultscore=0 bulkscore=0 clxscore=1015 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2510240001 definitions=main-2511040139 On 11/4/2025 5:59 PM, Konrad Dybcio wrote: > On 11/4/25 1:12 PM, Krishna Chaitanya Chundru wrote: >> The T_POWER_ON indicates the time (in μs) that a Port requires the port >> on the opposite side of Link to wait in L1.2.Exit after sampling CLKREQ# >> asserted before actively driving the interface. This value is used by >> the ASPM driver to compute the LTR_L1.2_THRESHOLD. >> >> Currently, the root port exposes a T_POWER_ON value of zero in the L1SS >> capability registers, leading to incorrect LTR_L1.2_THRESHOLD calculations. >> This can result in improper L1.2 exit behavior and can trigger AER's. >> >> To address this, program the T_POWER_ON value to 80us (scale = 1, >> value = 8) in the PCI_L1SS_CAP register during host initialization. This >> ensures that ASPM can take the root port's T_POWER_ON value into account >> while calculating the LTR_L1.2_THRESHOLD value. > Is 80us a meaningful value, or "just happens to work"? This value is given by hardware team. - Krishna Chaitanya. > > Konrad >