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 5717036405E for ; Wed, 21 Jan 2026 12:52:32 +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=1768999954; cv=none; b=ghYR3hmE5kB6bd3yDhdXMhK3qu6fPBy9wDVsfCXf2eTozFsSDJDMaQ7yADT+NIIg5WqVfcb2aD6/1CAHmSjXeRl7M1nVwdwsfMIj0CUCwsFrUY1VfUqswemPpnU1l4o/8M1F7ItHzAz6CO3CNiS74QIgVfnJqKSqJe/9MWEapSo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768999954; c=relaxed/simple; bh=rwSf8fNWqiNDBYgYMkPuKN7RGY1I7zi468jEYarcFXg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=caUDvguhAs3NEdrbrmWCauTtITlM3rZQE7HhrHw5okxL/u91NtSNHXqgUZONsVDaOjkjYCEzVJyIEs9wcheUyP+Nmt4/ffQIm1UwaBR6uMSYNF65lC5fpcIhGrvvPwN5WLoUbRqO2TxrRZkFHRnea0jhnLZ4of04rHNJUQrjUWU= 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=ebvK0CBa; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b=VgapmqDL; 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="ebvK0CBa"; dkim=pass (2048-bit key) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.b="VgapmqDL" Received: from pps.filterd (m0279862.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 60LA1VfD2840458 for ; Wed, 21 Jan 2026 12:52:31 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= Vm2c7TjrTcvjEHOS1OuxOVPHSsAoS1MO82JHEbyQX00=; b=ebvK0CBa7bhuGS5K L727dqEzVzP+f3RSR14AQImHB5doXAcZ0cxFc/c9LCobesB88dNQi+IXwPS6LRzG 0KDwsoZfJ6/yHXebbz5+RCVoF3F3jrTiuPEeFKCCz2K50QEGvm4ita4TFG9EkBKS AKhGRBfqwDXsc5hTqDYS81T34vm9GgavzWkvi1esdrekdGiCfyHbLZr27p1seu9Z OBTaBsW9x07f4UzuPCql3D8DF7UFdq+bfnI5tUkTUQ4MOh0OhNZK27/rfgErGrqz aaAbriBDo/wwxvcRKx+eAf46+q6YVDArtoUXKN7IeAyvoRwhYp50OHBe6DS+hLML 1L2jBw== Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4btqm1t18x-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Wed, 21 Jan 2026 12:52:31 +0000 (GMT) Received: by mail-qk1-f199.google.com with SMTP id af79cd13be357-8c52de12a65so165973085a.2 for ; Wed, 21 Jan 2026 04:52:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1768999950; x=1769604750; 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=Vm2c7TjrTcvjEHOS1OuxOVPHSsAoS1MO82JHEbyQX00=; b=VgapmqDL1WfqWsReskyK5QL7Bp420SeYyRtFLNpC45osi+8YcIfdQcWHwSSfobGc82 fmshSmdyFvDSGh8J3bemxhkqXYVypJwbK7hOEPyiQBVSFtQHqPeuHC7VjnE6fdy5qFoi ukRLKhdhyOvxaA55nIO0ORvkJExBPQsvk3kUYQh1WrZAGrPM+ECnk3he2KUiP9TcenA8 sPxe8x/Uht8hTCmRqkiyG0zQH131WqTiaGbpCk3KwWoWdisVPi6CN5NTNLWlHZAQqNN+ T0ycPE5Ee/WoEbhJ6rtKM91hrb+BYq7qJg0uxR2O8blyW0J0vlT/1vELOCvuWwLdis4h jU/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768999950; x=1769604750; h=content-transfer-encoding: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; bh=Vm2c7TjrTcvjEHOS1OuxOVPHSsAoS1MO82JHEbyQX00=; b=keN6kFBp8Luk3vdvYAymzpOQFtREyWH+NpQ3CXrAt/OCugzSW5jDZf3L2wHzDgFC3c CMuk7zveTkQBSn/As1hv9znCbKzoMbJbHE35eQq0bVEojC9lbPKKuJ1Equ9k3qfMTb2g nN0X5fOX4iNOUnJiF69hzyNF/Y2G91/E29xEPJw0UmIV3AFvztHCzCLIHxk9y08oA1Si D91yQ9EMzFeZEE/1srJ2mBJgfdTZ1Xk2sQdjz28eE6/5aN35OVeWj3pGJmhik535p6Iz NACIWYY/lSWdcr+/HSAoKMQXdrWyaO3FhTy9DiqTwOqncD06gaWuVOJMygChw6x6PpDc N8Qg== X-Forwarded-Encrypted: i=1; AJvYcCVE5d3X2jfjGWKnRtCf7UahJSyhLFr8FjxP28PtyK5J4l2DBAblsXii/UFwKBn3Zot/F5aOrCxE965jz4k=@vger.kernel.org X-Gm-Message-State: AOJu0Yznx8YO+Vd9/DN+xn+IZrZjHMX5CrJDlcTqtEJZjvfKrxZuoyyK MoTwikW6a9NHT/jaXWOxz+J/0L+wFUERckeC1ijgbsD7pLjmAkvaIvRSTngMLuvoW4Sd8MxCDsb SY1lqYIuA/LgjwrUhFPyIXIuMWIkuZ1XrN4uhPUbPl2pBdR+h78uAs3vooQpcIROP+UY= X-Gm-Gg: AZuq6aKZSHE8gcTSvWCJKvY2VEJ+I0djiGy/FL//IXSQCXLcLA48rD4SlZSwwWVZ4f3 fYAdIcRpiIvm23YGL4KwPOKzuWx7DpoNevd4jFMrEca9dHAwOEq+NSAy4Lj306rESy2yo2/UNCk NjMT6xSsRaGWnRqd9K5sxRJkI7WlDYP4+3aTN7u3CzK3GoyhMZqNYl4cPyETiuR/aijCoinmRu9 4bbQvCWtknIIZgfH5g/+SxDBrNqqEaEV+WDFhZhBLwKmPgAGKscaVm4m/RlsEQij8k4nG350elJ LXPFiUFRqRXWGLiQlflVKWVvrWEdr6PHWQoYX5HqrsETVmrDPEOL6jiXYkbiUElvWK2Mojf8Wvr uDYUgRUzB/GPEEkJZYK14/a0SpVM3TP7EOY63oQVtnvcaChjhNxsrV3cSOAwVzuuhq88= X-Received: by 2002:a05:620a:172a:b0:8b9:e0ea:af3b with SMTP id af79cd13be357-8c6ca3deb59mr626854785a.5.1768999950417; Wed, 21 Jan 2026 04:52:30 -0800 (PST) X-Received: by 2002:a05:620a:172a:b0:8b9:e0ea:af3b with SMTP id af79cd13be357-8c6ca3deb59mr626852985a.5.1768999949974; Wed, 21 Jan 2026 04:52:29 -0800 (PST) Received: from [192.168.119.254] (078088045245.garwolin.vectranet.pl. [78.88.45.245]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b8795169017sm1580399366b.18.2026.01.21.04.52.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 Jan 2026 04:52:29 -0800 (PST) Message-ID: <39e2bd90-8566-42d9-8ecd-6c5ba0f9747d@oss.qualcomm.com> Date: Wed, 21 Jan 2026 13:52:26 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] arm64: dts: qcom: SM8750: Enable CPUFreq support To: Akhil P Oommen , Jagadeesh Kona Cc: Ajit Pandey , Imran Shaik , Taniya Das , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Sibi Sankar , Jassi Brar , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio References: <20251211-sm8750-cpufreq-v1-0-394609e8d624@oss.qualcomm.com> <20251211-sm8750-cpufreq-v1-2-394609e8d624@oss.qualcomm.com> <908b64f1-f6ac-4c5e-9c72-1174cba62017@oss.qualcomm.com> <99796cc0-f29b-40d0-b8bb-ebcbcc950b23@oss.qualcomm.com> <996f47de-5900-4a3a-9372-e5ea3ae31c8b@oss.qualcomm.com> <417f77ba-a0b0-4ba5-824d-8814b776c557@oss.qualcomm.com> Content-Language: en-US From: Konrad Dybcio In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTIxMDEwOCBTYWx0ZWRfX0IDtQqGkbmbW ssa/246/vqHjoNG7y6XgZNRN7dBs5sUWbQghmlNvOQFd5HdTxNBVeafsk0PD1ksSbCWQWkEqW/w 8ujl8W0RBgWVkcK1lBr1SdWAyyqBAvvVL6uKJqdV0du/cs18h07GljRjKZYGGHhn7RKm/kZhida 9/jcdgO7bwBnip68uoSPTxVqXNGpG9j3DH4mTVaTnz7uY7cngqUoKuHH1odGYAiV1+b4ImF1Asc 9KcJJUukx9g4sx+3joHccZl75dwEu6oGoOWZjUNL4v7WV1XugFkr6eMVj8Q64u5L4tbT8psv9Lz hMySlLH6oWQK3Pc5ANE99QNPWah/GuSRZ8rpQDasnGjGhEbE69BoX6srDOPJa03iQ3bCAfB+8A/ 8kadeBanP3RkD88/GDumDMKJod9e7IQbhC/SguOLp9nQIJQjnqCADoN9KSA0CZTmrzz9MGKgorL VbmTjN1ce1y/sX2dCGQ== X-Proofpoint-ORIG-GUID: OOlQ60cb97b_AEWuwx0yHhmEzRW8wm2G X-Authority-Analysis: v=2.4 cv=dtnWylg4 c=1 sm=1 tr=0 ts=6970cc0f cx=c_pps a=HLyN3IcIa5EE8TELMZ618Q==:117 a=FpWmc02/iXfjRdCD7H54yg==:17 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=EUspDBNiAAAA:8 a=t3_i3bCFRmu7eDRSzYAA:9 a=QEXdDO2ut3YA:10 a=bTQJ7kPSJx9SKPbeHEYW:22 X-Proofpoint-GUID: OOlQ60cb97b_AEWuwx0yHhmEzRW8wm2G X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.20,FMLib:17.12.100.49 definitions=2026-01-21_01,2026-01-20_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 clxscore=1015 impostorscore=0 spamscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 adultscore=0 lowpriorityscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2601210108 On 1/21/26 1:47 PM, Akhil P Oommen wrote: > On 1/21/2026 5:06 PM, Konrad Dybcio wrote: >> On 1/20/26 9:54 PM, Akhil P Oommen wrote: >>> On 1/20/2026 8:13 PM, Konrad Dybcio wrote: >>>> On 1/20/26 12:25 PM, Akhil P Oommen wrote: >>>>> On 1/20/2026 3:44 PM, Konrad Dybcio wrote: >>>>>> On 1/19/26 8:00 PM, Akhil P Oommen wrote: >>>>>>> On 12/11/2025 12:32 AM, Jagadeesh Kona wrote: >>>>>>>> Add the cpucp mailbox, sram and SCMI nodes required to enable >>>>>>>> the CPUFreq support using the SCMI perf protocol on SM8750 SoCs. >>>>>>>> >>>>>>>> Signed-off-by: Jagadeesh Kona >>>>>>> >>>>>>> Just curious, does this patch enable thermal mitigation for CPU clusters >>>>>>> too? >>>>>> >>>>>> If nothing changed, we have lets-not-explode type mitigations via LMH, >>>>>> but lets-not-burn-the-user would require a skin temp sensor to be >>>>>> wired up, which then could be used to enable some cooling action >>>>> >>>>> In some chipsets, I have noticed that the gpu cooling device throttles >>>>> GPU to the lowest OPP even with not-so-heavy GPU workloads, making it >>>>> unusable-ly slow. My hypothesis was that it was due to unmitigated CPU >>>>> temperature tripping up GPU Tsens. >>>>> >>>>> So, I am wondering if there are any additional CPU cooling related >>>>> changes required to get a reasonable overall performance under thermal >>>>> constraints. >>>> >>>> Yes, something like the aforementioned skin-temp sensor at least.. >>> >>> I suppose this sensor is off-chip and slow to react. >> >> Yes, this would be placed somewhere on the chassis of the device to >> reflect the actual temperature that the user could experience (since >> there are regulations about maximum values of that) >> >>>> Today Linux will not throttle the CPUs at all (they're not even declared >>>> as cooling devices) and we sorta agreed that in general it's a good thing >>>> (tm), because otherwise we'd be coding in a cooling profile into the SoC >>>> DTSI without taking into account the cooling capabilities of a given end >>>> device (i.e. in an extreme case, a PC with SM8650 with a cooler that's >>>> 3kg of aluminium vs a Steam Frame headset where the SoC is centimeters >>>> away from your face) >>>> >>>> Currently, we have cooling policies for devices with fans and the only >>>> other action is based on a skin temperature sensor (sc8280xp + x13s). >>>> Everything else is left up to the LMH defaults. AFAIK work is ongoing to >>>> create a more informed solution, that would have to (quite obviously) >>>> live in userland. >>> >>> I can understand that the skin-temp based mitigation is influenced by >>> various design decision outside of the SoC die. But I think there should >>> an on-chip sensor based mitigation which is fast and usually for a short >>> duration which helps to avoid extreme temperature or violating the >>> maximum operating point of the chipset. I guess it should depend only on >>> the SoC characteristics as it is a last resort. It may be implemented in >>> SW (like cooling device for Adreno GPU) or in HW. Probably the LMH >>> hardware you mentioned offers this functionality for CPU clusters. I >>> have no clue. :( >> >> Yes, the CPUs are covered. > > Does this LMH based thermal migitation require any initialization from > Linux? If yes, could you please share a link to a patch which enables it > for any recent chipset for my reference? It used to, see drivers/thermal/qcom/lmh.c I believe it went away roughly with 8250 where the firmware now takes care of all that. FYI I think it first appeared with 8994 Konrad