From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=205.220.180.131 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794369990; b=bNuzWOYzCcSTMJt9fkenP/B0OU4smSyNQ/ec1pJYxETbUCjqoduHfPutnzt1tzwbsGb+ MFZ+6EYSQidCvRzWAn40DI7tUKGY+Q8JMy/tHXlMq3C+XsD3QzC74+PSnl7mW5KZsI3Hi FcYH2DQ5rEb3paURfvHwPEIR0/Fz3MxAtP5L6AVFDX9GM3MBrFHEwPE0tzSJvD6pdQDYP 2qbX06HGL2law2HNzlthq4nBCH/k3T2Q6WZTZsfOaM1cjR03hu54+6+08/FRq95A0nJKC qeOwyMa1C/2ViRuvXxDqbrHkLAGfWUATvFelBq1DLQGqS9j7ig87sSjcuYNo0lo6qIQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794369990; h=DMARC-Filter:Received:DKIM-Signature:Received:Received: DKIM-Signature:X-Google-DKIM-Signature:X-Gm-Message-State:X-Gm-Gg: X-Received:X-Received:Received:Message-ID:Date:MIME-Version: User-Agent:Subject:To:Cc:References:Content-Language:From:In-Reply-To: Content-Type:Content-Transfer-Encoding:X-Proofpoint-Spam-Details-Enc: X-Proofpoint-ORIG-GUID:X-Proofpoint-GUID:X-Authority-Analysis: X-Proofpoint-Spam-Info:X-Proofpoint-Virus-Version: X-Proofpoint-Spam-Details; bh=X0N+eXPcaXDvyNvT+oaZCqoDi7RGGzFN8kPT+kr2B2g=; b=atER0co9o8jNn8O6SKBu/Wwcub1MZaO8GTDObAhjdmafXBgihpCetdKjCn7e+LdbTfSI yvH0ICp5KJD3fK1KG6tW+Swcf/MZeRUKK1Xm3SYQZ8+6Cj8rMZsu0db9v/DYJY5GypHiC B+gAiRL/sGIF7++bmeIwjAKyy0jGxHUqMF9Zjxj92brfbMP7g02O5KV/rCc+79N/KZxYF P/ke5vk/WUDHDF46BIoIlkMKTv4Sjc95+aRQalKnkjF72gED9O5oy0hgkAuQhjpwB6mQp 9zJXnuNAGKnPvtaGnNf1jOjc+EP5sH73OuBRCIlnTK5fbOp9EYnSg7cObdGH7G48yUQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass header.d=qualcomm.com header.i=@qualcomm.com header.a=rsa-sha256 header.s=qcppdkim1 header.b=mcL7E54o; dkim=pass header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=UHRtWC8a; arc=none smtp.remote-ip=205.220.180.131 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 088C1606A332 for ; Wed, 11 Nov 2026 04:06:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 088C1606A332 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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.a=rsa-sha256 header.s=qcppdkim1 header.b=mcL7E54o; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=UHRtWC8a Received: from pps.filterd (m0279873.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6AB1tZLj923308 for ; Wed, 11 Nov 2026 04:06:29 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= X0N+eXPcaXDvyNvT+oaZCqoDi7RGGzFN8kPT+kr2B2g=; b=mcL7E54ozQDbMzmA mNpGJabuuRSkm1Vm6Iutj5fzqHDToSWvXi1Z3N3PWkoqcXxx5lUE2AX6Uc7XxFEc Mw5xjro7woOr2ZRIAe3EJS0fNZOjXjSl06H7AZuU62I6JK1/Me3CuBDf51crIaBF vgMAMDAq8vodazyRJPY5s+zJkO72Dz8ARIEmFlsXyRqJbEfAlzndz+E1Kl7fFVkL X5fFMUGyfCy25vKKmnfYNEtpCUiDOwmevJm/tdNyUw9+igItkG1DDK2V8Z0quL9R fxpLRcNdUywVS0/ql9XKrAqLuFAdVS7JmRWjhsKHXOSRjEFKq/TrOT6t3+/lUaKP Ve+jdA== Received: from mail-dy1-f200.google.com (mail-dy1-f200.google.com [74.125.82.200]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4hvcpegwmy-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Wed, 11 Nov 2026 04:06:28 +0000 (GMT) Received: by mail-dy1-f200.google.com with SMTP id 5a478bee46e88-30bcb065bfdso4782541eec.0 for ; Tue, 10 Nov 2026 20:06:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1794369988; x=1794974788; darn=vger.kernel.org; h=content-transfer-encoding:content-type: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 :content-type; bh=X0N+eXPcaXDvyNvT+oaZCqoDi7RGGzFN8kPT+kr2B2g=; b=UHRtWC8auY3z1Wnca5nuuZH3nXi7e3tS4BjaiWty1RFvQpTPU/TmP56yn2+jKxqQwm s3JeDROmjTn3ux9ju27A9Y7x3rYkenKGlX18cTq4sUVSO8bjB6K2KhkdFwkssAexfkyi 3qSP0VmlW7ABZqkpAgtJpXAdFuR3us65ZFXgfKdfWKdCnDh0reuMIJ1jHvyEuR9a1Sfk 5BTiZlo0C5qgA/57H3GT+tKfS1HNTVlkvh2No3oj5rfC8f5WB4lQnoBD8FbiFOfIRZjF x4ORIETRiYpadsjT49gI2MxMlwvejMH9X9RCpsCFiLtQJg7DwjFsnuYxSjeL8iYyQzl7 fe2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794369988; x=1794974788; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=X0N+eXPcaXDvyNvT+oaZCqoDi7RGGzFN8kPT+kr2B2g=; b=C12Gcml/BdujM3p2X5mUmLuaJQYWoTAvKO5s4nP/Soj9/TAhJWGLXgHXsWBcSx5g7w 0X/j9K8kYpSNjriayhMcdyOwk65Wxx2n5xOMqPphwEqgapgSN2+01vo2hcO/lPRcyzix 5bE0AxsFvK+L1ZNEeXhNH1Pmv+q3Eac/EjnE+vk7LN/avMlSrLaYuqeGzj0eEWz0vrQK wZux4eQHEgq/yD4QVHtd4v0bQwWU4RHXTdN7LUngiyBmEwJZv1LquOLOcyp/nabPAJok f2CvN86T1VJGEFMXWgESqkUX6rpwU3JS/DMWkc8QyxJRvF2JZo3izmG77wB1TC350zeX P2Gg== X-Gm-Message-State: APuU4Z/1CC2PvjNIWT2OwBv5l0OUb0QLfCksz9qjkcLoBVQx2Kmytz8r xRDdWeyxHbB4X9gzXGpzZ4MStxAi/gsHo75h4Gl8vMc9GOB8Pu8u2qMvkNwgEw+Iawim+iM+aJQ 7bdGC0GhWRty4vvLyVZNNHjcwbFrsBWe/4lab8SFN9LixYUDlJKVqZ6fX3ud4BiU= X-Gm-Gg: AYBFou1Wy1hhRBlxleKFWDtqw3zPmOxsPtuo3aUxYNB8LoeJszLYEqeHT2NByxxNnyi fgv7bPYog1ChJ0wuhK/Ew1NsP5TokSKaY9tz2aI/aEF45aOTmfoI6Z0lqh/IMvRjtYbYbORWBj1 XJgT5Dy2sveAlpClpA4A70FCcE26vcJgaRVwTHVD89icG2+P9Hs3xieWQOHlbkxAY6elGW+Eo3h JWnsDIfndrl/417CODpJjDW3XgFCm30Y8kq8TRsSpTbvK1qQmsn4eeY1e8bbrfyvsn5Hi3o5A8l ovrsdATI5BAbPHZeFBbwKD3evzHNcM+5TDJB6DXMhIY9101BZf+YlZcewJpLkP96lzgjSrAxJvP CFpusA5BQD+DSYY0rtFaNuCaPoeoN3fImLoz7Eq63yOV5zC4pcC/W9NvgxHHemFRS/9QY03SOGN Dq/8+7AS3N+VaxVhET6rt/WykWEp0Euy2/sQRbxgsZ X-Received: by 2002:a05:7022:5f08:b0:1b2:471f:c4c with SMTP id a92af1059eb24-1b3c030fcd1mr1051378c88.19.1794369987526; Tue, 10 Nov 2026 20:06:27 -0800 (PST) X-Received: by 2002:a05:7022:5f08:b0:1b2:471f:c4c with SMTP id a92af1059eb24-1b3c030fcd1mr1051345c88.19.1794369986889; Tue, 10 Nov 2026 20:06:26 -0800 (PST) Received: from [10.217.219.121] ([202.46.22.19]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-1b3b5890e04sm11420079c88.2.2026.11.10.20.06.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 10 Nov 2026 20:06:26 -0800 (PST) Message-ID: Date: Wed, 11 Nov 2026 09:36:21 +0530 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] usb: dwc3: Update nominal max votes for qcom usb To: Akash Kumar , Konrad Dybcio Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, Greg Kroah-Hartman , Bjorn Andersson , Konrad Dybcio , Rob Herring , Dmitry Baryshkov , Krzysztof Kozlowski , Conor Dooley References: <20261105100626.2003771-1-akash.kumar@oss.qualcomm.com> <875bc537-af18-4d4e-86d0-9bf0ed7992db@oss.qualcomm.com> Content-Language: en-US From: Krishna Kurapati In-Reply-To: <875bc537-af18-4d4e-86d0-9bf0ed7992db@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTExMDAxNiBTYWx0ZWRfX9nAj5eXlqjAN mHwKjTh1q9XSRnAVsjD12T50zVO1ux/v/7P2SSVmtHJL9BE+IVm1W2exQbD4MhvIK97vljuIt+s 1UDZMKBEhDwVKieW0U9Oe0JA1t6cjTby0Jk38XB/7tfvhyf3dwpD1jV77u4nbL0M9U9n+re3VHp Lw5k/6S6cOWUgbZq8xf09uydFA8Gp+Ml+nxwGKQQ1qQqUgW2h6FcIOIOYPwoSvvZlB5S2ePoYQS smHSBw+hDp1xoTmhRrn962hj/baN6ZXmKax77YU3sBhn8DXRgBsh66KKfUCQ8ozer65VzmoSvD3 0nE0nI+GJVUeB4ZR+DegWFooY84j5wcE2KmkV4J0Ki9TfvstW2iwQKxgU7j/OkKdW+2yFAMLAtj KPnUgbqhRRUcJMcg3PpTe9M34EDGKGhKNgEqBwHa6SCDfcZqmp+fRzzI2aMmOPKItxptGHwvWk/ Es7lrBcdRKgp75ZILyw== X-Proofpoint-ORIG-GUID: wyeYEJd28VxyVSBHriMXivcmXbmXYI-c X-Proofpoint-GUID: wyeYEJd28VxyVSBHriMXivcmXbmXYI-c X-Authority-Analysis: v=2.4 cv=RfAFmFtv c=1 sm=1 tr=0 ts=6af3e9c4 cx=c_pps a=PfFC4Oe2JQzmKTvty2cRDw==:117 a=fChuTYTh2wq5r3m49p7fHw==:17 a=IkcTkHD0fZMA:10 a=zJRp6_cAMcgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=rJkE3RaqiGZ5pbrm-msn:22 a=dkA42MIeFly6lUBFm3wA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=6Ab_bkdmUrQuMsNx7PHu:22 X-Proofpoint-Spam-Info: AW1haW4tMjYxMTExMDAxNiBTYWx0ZWRfX9NkPqt4dlZJY vNCIMFNi7tIllNDBV0FFi4vlGW32GymSGFmn7MzJgH7tvEACJZ6b7ZhFtr7xxoD0csGBtzivnCi P0yBey8WahY73I2zzkvUW5E5lEMiXxc= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-11_01,2026-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 phishscore=0 malwarescore=0 spamscore=0 adultscore=0 clxscore=1015 bulkscore=0 lowpriorityscore=0 suspectscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2611040001 definitions=main-2611110016 On 11/8/2026 12:52 PM, Akash Kumar wrote: > > On 05-11-2026 21:11, Konrad Dybcio wrote: >> On 11/5/26 11:02 AM, Akash Kumar wrote: >>> Increase the nominal max USB memory bandwidth vote to let DDR scale >>> higher within its nominal corner, fixing glitches seen during >>> simultaneous USB audio use cases. >>> >>> USB_MEMORY_PEAK_SS_BW is raised from 2500 MB/s to 4500 MB/s (+2000 >>> MB/s, ~1.8x). This ICC vote does not by itself determine DDR >> Can we scale this depending of the real speed of the connected >> device adjusted for the real data throughput? i.e. if we walk >> the tree and min/max as appropriate, we end up with say 10G >> wire speed, out of which we can shave off some static overhead >> >> 4500 MB/s is 36 Gb/s which is way beyond what USB3 can do, in >> any configuration. >> >> Konrad >> >> Hi Konrad, >> >> Two things worth separating here: >> >> 1) The ICC vote is not a USB wire-speed requirement, so it >> shouldn't be compared directly against the USB3 line rate. This >> number is a DDR/memory-interconnect bandwidth vote; the platform's >> interconnect/OPP table is what maps a given vote to a DDR >> frequency/voltage corner. 4500 MB/s doesn't mean we expect 36 Gb/s >> on the wire - it means we want the memory subsystem's bus matrix to >> have enough headroom that the platform's table picks the higher >> in-corner DDR frequency instead of pinning it at the lower one. The >> vote intentionally carries margin for the aggregate memory traffic >> of the whole USB subsystem (descriptors, buffering, concurrent >> audio capture/playback, etc.), not just the raw bulk payload of one >> device, which is why it doesn't map 1:1 to link speed. >> >> 2) We do already have a speed-based split for this, just not a >> per-device dynamic one. dwc3_qcom_interconnect_init() picks between >> the HS and SS vote pairs based on usb_get_maximum_speed() of the >> controller: >> >>      max_speed = usb_get_maximum_speed(qcom->dwc.dev); >>      if (max_speed >= USB_SPEED_SUPER || max_speed == USB_SPEED_UNKNOWN) >>              ret = icc_set_bw(qcom->icc_path_ddr, >>                              USB_MEMORY_AVG_SS_BW, >> USB_MEMORY_PEAK_SS_BW); >>      else >>              ret = icc_set_bw(qcom->icc_path_ddr, >>                              USB_MEMORY_AVG_HS_BW, >> USB_MEMORY_PEAK_HS_BW); >> Hi Akash, Rather than relying on DT parameter to determine ICC bandwidth, we can do the following: a) In host mode, we can register notifier to usb core and based on device connection speed at runtime, we can modify the ICC bandwidth. If its High-Speed, we can scale back to SVS. This reference is present in downstream. b) For device mode, we can register a post-conndone glue hook to dwc3 core and depending on connection speed (DSTS regsiter read), we can set appropriate ICC vote. This is not tried on downstream but I think it must work fine. Regards, Krishna, >> This patch only touches the SS tier's peak value; a controller >> whose maximum speed is HS is unaffected. It's set once at probe >> based on the controller's maximum capability rather than walking >> the topology for the actually-negotiated speed of whatever is >> plugged in at a given moment, so it's intentionally a worst-case >> value rather than a precise per-device figure - which is also why >> it's sized for the glitch we saw under concurrent audio+bulk load >> rather than for a single device's best-case throughput. >> >> Thanks, >> Akash >