From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 3E75922DC5D; Tue, 14 Jan 2025 09:37:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736847422; cv=none; b=oB/aktqZug03DAAoNWSUuluhgL3IcTYgk2pZZlG35YNWxoXf4LBc+kkPHs+ptfyvXwtuVKynk2sPGUP+P+YhyrHK5vgj1dFWgxQLqb+fCzXQe4ZKufWfRc3Jy1o3oo1pDqjzDLg38DMUgSU6qnCmyyAFZzyPbPZ0iGHpuwwvXao= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736847422; c=relaxed/simple; bh=aEHfS9NOn4dw70JfggUmYvKT8u4xG2BPT3tE/Wc//go=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=EElfggPRxG2evV1KGKS5dqHxzW1xBBCG/vh44GJYECfYivXAkHg9/cIfv9Xoey5nlIkVEIbrIwDgyjYlTisyn3++oGizJHtQre5bPCGrPn+vGka755HedHgyo076aSswIoeWyPmIXo/5CHH+sLE3xsrzkzh8rcHduCR1QViBOpM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=MzHTDSZS; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="MzHTDSZS" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 50E25i7r019939; Tue, 14 Jan 2025 09:36:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=njf12d QUQxsxqC/FQJPwNc+LJpENatjRic/jsHe/6KQ=; b=MzHTDSZSQ9rAyAOCr3i93C WX0+d9QrAVsoym/eYpt2BZZAVGmEazsiawKG1PyvEaFPpQBYVtddlB+bkagQGycl fIx4q5pO9/53uAYbhEFEqsoaxhoUzF3dw2v0ok7lZheZFEpk2js8fx8Ck7o0pEIk XCMWfnRWN/Nuhiaq1NAmPsThb1h2/2WmaNtSgO0uUEBoTdfTLZhpp6rMeEusco5G 7r+LmY+vCpZusCgW25Y+O+YooRFUajlpXNiIfxM21CbnNd7NiklV1OCwTqp2IfoO 8JSIPpzGhYZZ28WCyvj37gnGBx+Kp+uAlesn4L3eFYwHspcNgzh2oa349IUonexA == Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4454a5c72p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 14 Jan 2025 09:36:25 +0000 (GMT) Received: from m0353725.ppops.net (m0353725.ppops.net [127.0.0.1]) by pps.reinject (8.18.0.8/8.18.0.8) with ESMTP id 50E9YI93005487; Tue, 14 Jan 2025 09:36:24 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4454a5c72k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 14 Jan 2025 09:36:24 +0000 (GMT) Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 50E92uFc002734; Tue, 14 Jan 2025 09:36:23 GMT Received: from smtprelay04.dal12v.mail.ibm.com ([172.16.1.6]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4443by2p6k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 14 Jan 2025 09:36:23 +0000 Received: from smtpav06.dal12v.mail.ibm.com (smtpav06.dal12v.mail.ibm.com [10.241.53.105]) by smtprelay04.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 50E9aNOX17629712 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 14 Jan 2025 09:36:23 GMT Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 30E3958043; Tue, 14 Jan 2025 09:36:23 +0000 (GMT) Received: from smtpav06.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 77C4A58055; Tue, 14 Jan 2025 09:36:19 +0000 (GMT) Received: from [9.171.92.251] (unknown [9.171.92.251]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 14 Jan 2025 09:36:19 +0000 (GMT) Message-ID: <0a053cef86001953b34fd199b551b96100fcca70.camel@linux.ibm.com> Subject: Re: [PATCH v2] PCI/portdrv: Disable bwctrl service if port is fixed at 2.5 GT/s From: Niklas Schnelle To: Geert Uytterhoeven , Niklas Schnelle Cc: Ilpo =?ISO-8859-1?Q?J=E4rvinen?= , Bjorn Helgaas , Lukas Wunner , linux-pci@vger.kernel.org, Rob Herring , Krzysztof Wilczy??ski , "Maciej W . Rozycki" , Jonathan Cameron , Alexandru Gagniuc , Krishna chaitanya chundru , Srinivas Pandruvada , "Rafael J . Wysocki" , linux-pm@vger.kernel.org, Smita Koralahalli , linux-kernel@vger.kernel.org, Daniel Lezcano , Amit Kucheria , Zhang Rui , Christophe JAILLET , Mika Westerberg , Lorenzo Pieralisi , Stephen Rothwell Date: Tue, 14 Jan 2025 10:36:18 +0100 In-Reply-To: References: <20241213-fix_bwctrl_thunderbolt-v2-1-b52fef641dfc@kernel.org> Autocrypt: addr=schnelle@linux.ibm.com; prefer-encrypt=mutual; keydata=mQINBGHm3M8BEAC+MIQkfoPIAKdjjk84OSQ8erd2OICj98+GdhMQpIjHXn/RJdCZLa58k /ay5x0xIHkWzx1JJOm4Lki7WEzRbYDexQEJP0xUia0U+4Yg7PJL4Dg/W4Ho28dRBROoJjgJSLSHwc 3/1pjpNlSaX/qg3ZM8+/EiSGc7uEPklLYu3gRGxcWV/944HdUyLcnjrZwCn2+gg9ncVJjsimS0ro/ 2wU2RPE4ju6NMBn5Go26sAj1owdYQQv9t0d71CmZS9Bh+2+cLjC7HvyTHKFxVGOznUL+j1a45VrVS XQ+nhTVjvgvXR84z10bOvLiwxJZ/00pwNi7uCdSYnZFLQ4S/JGMs4lhOiCGJhJ/9FR7JVw/1t1G9a UlqVp23AXwzbcoV2fxyE/CsVpHcyOWGDahGLcH7QeitN6cjltf9ymw2spBzpRnfFn80nVxgSYVG1d w75ksBAuQ/3e+oTQk4GAa2ShoNVsvR9GYn7rnsDN5pVILDhdPO3J2PGIXa5ipQnvwb3EHvPXyzakY tK50fBUPKk3XnkRwRYEbbPEB7YT+ccF/HioCryqDPWUivXF8qf6Jw5T1mhwukUV1i+QyJzJxGPh19 /N2/GK7/yS5wrt0Lwxzevc5g+jX8RyjzywOZGHTVu9KIQiG8Pqx33UxZvykjaqTMjo7kaAdGEkrHZ dVHqoPZwhCsgQARAQABtChOaWtsYXMgU2NobmVsbGUgPHNjaG5lbGxlQGxpbnV4LmlibS5jb20+iQ JXBBMBCABBAhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAhkBFiEEnbAAstJ1IDCl9y3cr+Q/Fej CYJAFAmWVooIFCQWP+TMACgkQr+Q/FejCYJCmLg/+OgZD6wTjooE77/ZHmW6Egb5nUH6DU+2nMHMH UupkE3dKuLcuzI4aEf/6wGG2xF/LigMRrbb1iKRVk/VG/swyLh/OBOTh8cJnhdmURnj3jhaefzslA 1wTHcxeH4wMGJWVRAhOfDUpMMYV2J5XoroiA1+acSuppelmKAK5voVn9/fNtrVr6mgBXT5RUnmW60 UUq5z6a1zTMOe8lofwHLVvyG9zMgv6Z9IQJc/oVnjR9PWYDUX4jqFL3yO6DDt5iIQCN8WKaodlNP6 1lFKAYujV8JY4Ln+IbMIV2h34cGpIJ7f76OYt2XR4RANbOd41+qvlYgpYSvIBDml/fT2vWEjmncm7 zzpVyPtCZlijV3npsTVerGbh0Ts/xC6ERQrB+rkUqN/fx+dGnTT9I7FLUQFBhK2pIuD+U1K+A+Egw UiTyiGtyRMqz12RdWzerRmWFo5Mmi8N1jhZRTs0yAUn3MSCdRHP1Nu3SMk/0oE+pVeni3ysdJ69Sl kCAZoaf1TMRdSlF71oT/fNgSnd90wkCHUK9pUJGRTUxgV9NjafZy7sx1Gz11s4QzJE6JBelClBUiF 6QD4a+MzFh9TkUcpG0cPNsFfEGyxtGzuoeE86sL1tk3yO6ThJSLZyqFFLrZBIJvYK2UiD+6E7VWRW 9y1OmPyyFBPBosOvmrkLlDtAtyfYInO0KU5pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNjaG5lbGxlQ GlibS5jb20+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAAstJ1IDCl9y 3cr+Q/FejCYJAFAmWVoosFCQWP+TMACgkQr+Q/FejCYJB7oxAAksHYU+myhSZD0YSuYZl3oLDUEFP 3fm9m6N9zgtiOg/GGI0jHc+Tt8qiQaLEtVeP/waWKgQnje/emHJOEDZTb0AdeXZk+T5/ydrKRLmYC 6rPge3ue1yQUCiA+T72O3WfjZILI2yOstNwd1f0epQ32YaAvM+QbKDloJSmKhGWZlvdVUDXWkS6/m aUtUwZpddFY8InXBxsYCbJsqiKF3kPVD515/6keIZmZh1cTIFQ+Kc+UZaz0MxkhiCyWC4cH6HZGKR fiXLhPlmmAyW9FiZK9pwDocTLemfgMR6QXOiB0uisdoFnjhXNfp6OHSy7w7LTIHzCsJoHk+vsyvSp +fxkjCXgFzGRQaJkoX33QZwQj1mxeWl594QUfR4DIZ2KERRNI0OMYjJVEtB5jQjnD/04qcTrSCpJ5 ZPtiQ6Umsb1c9tBRIJnL7gIslo/OXBe/4q5yBCtCZOoD6d683XaMPGhi/F6+fnGvzsi6a9qDBgVvt arI8ybayhXDuS6/StR8qZKCyzZ/1CUofxGVIdgkseDhts0dZ4AYwRVCUFQULeRtyoT4dKfEot7hPE /4wjm9qZf2mDPRvJOqss6jObTNuw1YzGlpe9OvDYtGeEfHgcZqEmHbiMirwfGLaTG2xKDx4g2jd2z Ocf83TCERFKJEhvZxB3tRiUQTd3dZ1TIaisv/o+y0K05pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNj aG5lbGxlQGdtYWlsLmNvbT6JAlQEEwEIAD4CGwEFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQSds ACy0nUgMKX3Ldyv5D8V6MJgkAUCZZWiiwUJBY/5MwAKCRCv5D8V6MJgkNVuEACo12niyoKhnXLQFt NaqxNZ+8p/MGA7g2XcVJ1bYMPoZ2Wh8zwX0sKX/dLlXVHIAeqelL5hIv6GoTykNqQGUN2Kqf0h/z7 b85o3tHiqMAQV0dAB0y6qdIwdiB69SjpPNK5KKS1+AodLzosdIVKb+LiOyqUFKhLnablni1hiKlqY yDeD4k5hePeQdpFixf1YZclGZLFbKlF/A/0Q13USOHuAMYoA/iSgJQDMSUWkuC0mNxdhfVt/gVJnu Kq+uKUghcHflhK+yodqezlxmmRxg6HrPVqRG4pZ6YNYO7YXuEWy9JiEH7MmFYcjNdgjn+kxx4IoYU O0MJ+DjLpVCV1QP1ZvMy8qQxScyEn7pMpQ0aW6zfJBsvoV3EHCR1emwKYO6rJOfvtu1rElGCTe3sn sScV9Z1oXlvo8pVNH5a2SlnsuEBQe0RXNXNJ4RAls8VraGdNSHi4MxcsYEgAVHVaAdTLfJcXZNCIU cZejkOE+U2talW2n5sMvx+yURAEVsT/50whYcvomt0y81ImvCgUz4xN1axZ3PCjkgyhNiqLe+vzge xq7B2Kx2++hxIBDCKLUTn8JUAtQ1iGBZL9RuDrBy2rR7xbHcU2424iSbP0zmnpav5KUg4F1JVYG12 vDCi5tq5lORCL28rjOQqE0aLHU1M1D2v51kjkmNuc2pgLDFzpvgLQhTmlrbGFzIFNjaG5lbGxlIDx uaWtzQGtlcm5lbC5vcmc+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAA stJ1IDCl9y3cr+Q/FejCYJAFAmWVoosFCQWP+TMACgkQr+Q/FejCYJAglRAAihbDxiGLOWhJed5cF kOwdTZz6MyYgazbr+2sFrfAhX3hxPFoG4ogY/BzsjkN0cevWpSigb2I8Y1sQD7BFWJ2OjpEpVQd0D sk5VbJBXEWIVDBQ4VMoACLUKgfrb0xiwMRg9C2h6KlwrPBlfgctfvrWWLBq7+oqx73CgxqTcGpfFy tD87R4ovR9W1doZbh7pjsH5Ae9xX5PnQFHruib3y35zC8+tvSgvYWv3Eg/8H4QWlrjLHHy2AfZDVl 9F5t5RfGL8NRsiTdVg9VFYg/GDdck9WPEgdO3L/qoq3Iuk0SZccGl+Nj8vtWYPKNlu2UvgYEbB8cl UoWhg+SjjYQka7/p6tc+CCPZ8JUpkgkAdt7yXt6370wP1gct2VztS6SEGcmAE1qxtGhi5Kuln4ZJ/ UO2yxhPHgoW99OuZw3IRHe0+mNR67JbIpSuFWDFNjZ0nckQcU1taSEUi0euWs7i4MEkm0NsOsVhbs 4D2vMiC6kO/FqWOPmWZeAjyJw/KRUG4PaJAr5zJUx57nhKWgeTniW712n4DwCUh77D/PHY0nqBTG/ B+QQCR/FYGpTFkO4DRVfapT8njDrsWyVpP9o64VNZP42S+DuRGWfUKCMAXsM/wPzRiDEVfnZMcUR9 vwLSHeoV7MiIFC0xIrp5ES9R00t4UFgqtGc36DV71qjR+66Im0= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.2 (3.54.2-1.fc41) Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: b9Ti87pIYGEnZ9YqfjVBaz9dVA8pjzQ6 X-Proofpoint-ORIG-GUID: -Fowpbzi03tjFWChVdDAx2dbZAx9FdmR X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 priorityscore=1501 suspectscore=0 phishscore=0 mlxlogscore=999 spamscore=0 impostorscore=0 clxscore=1011 lowpriorityscore=0 bulkscore=0 malwarescore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501140078 On Tue, 2025-01-14 at 09:50 +0100, Geert Uytterhoeven wrote: > On Fri, Dec 13, 2024 at 9:56=E2=80=AFPM Niklas Schnelle = wrote: > > Trying to enable bwctrl on an Intel JHL7540 (Titan Ridge) based > > Thunderbolt port causes a boot hang on at least some systems though the > > exact reason is not yet understood. As per the spec Thunderbolt PCIe > > Downstream Ports have a fake Max Link Speed of 2.5 GT/s (USB4 v2 sec > > 11.2.1): > >=20 > > "Max Link Speed field in the Link Capabilities Register set to 0001b > > (data rate of 2.5 GT/s only). > > Note: These settings do not represent actual throughput. > > Throughput is implementation specific and based on the USB4 Fabric > > performance." > >=20 > > More generally if 2.5 GT/s is the only supported link speed there is no > > point in throtteling as this is already the lowest possible PCIe speed > > so don't advertise the capability stopping bwctrl from being probed on > > these ports. > >=20 > > The PCIe r6.2 specification section 7.5.3.18 recommends to primarily > > utilize the Supported Link Speeds Vector instead of the Max Link Speeds > > field to prevent confusion if future specifications allow devices not > > to support lower speeds. This concern does not apply however when > > specifically targeting devices claiming support only for 2.5 GT/s. > >=20 > > Link: https://lore.kernel.org/linux-pci/Z1R4VNwCOlh9Sg9n@wunner.de/ > > Fixes: 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as PCI= e BW controller") > > Tested-by: Niklas Schnelle > > Reviewed-by: Ilpo J=C3=A4rvinen > > Reviewed-by: Mika Westerberg > > Signed-off-by: Niklas Schnelle > > --- > > Note: This issue causes a boot hang on my personal workstation. > >=20 > > While there is an ongoing discussion about generalizing this to all > > devices with a single supported speed. It turns out however that in my > > case dev->supported_speeds incorrectly claims 2.5-8 GT/s requiring > > a seperate second fix. So in the interest of simplicity and because I'l= l > > be out from the 19th until January, I'd like to propose to do this simp= le > > fix to the boot hang now and take the time to figure out a more general > > approach afterwards. > > --- > > Changes in v2: > > - Improve commit message to mention the specific controller and > > why using the Max Link Speeds field should be fine here. > > - Add a comment (Lukas) > > - Add R-b's (no change to logic). > > - Link to v1: https://lore.kernel.org/r/20241207-fix_bwctrl_thunderbolt= -v1-1-b711f572a705@kernel.org >=20 > This is now commit e50e27a613db6f18 ("PCI/portdrv: Disable bwctrl > service if port is fixed at 2.5 GT/s") in pci/next, which conflicts > with commit 774c71c52aa48700 ("PCI/bwctrl: Enable only if more than > one speed is supported") in v6.13-rc4. >=20 > Gr{oetje,eeting}s, >=20 > Geert Oh, that's not right, good catch. This patch is superseded by "PCI/bwctrl: Enable only if more than one speed is supported" and should be dropped. Sorry if that wasn't clear from the the limited context of this patch discussion. @Bjorn I think this needs to be taken care of by you? Thanks, Niklas