From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f67.google.com (mail-ej1-f67.google.com [209.85.218.67]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1029914D2B7; Thu, 7 Aug 2025 01:55:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.67 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754531707; cv=none; b=E3v3DvmbLKaC1QeKkK2hmZtwnbHTxG6ydbfZhGJfIYKxCCu3MnTTWn23d9XL2W7R0YDyFE3N9d58XP/qOsX9NXSr8yMimyc3en36/nUKnvMqzpCuspeHOq4dX/4aRZO1pcsAWg2g1J8TQ41DpjooBG1Z1m4FweiWlECBxBvstsw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754531707; c=relaxed/simple; bh=xIemcRtj/buSKba0olwitJryOOJRnALqFmIOZ32ilbk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=EWRM5NZx3pevXkBaF4EZDzEFYGqljd6Izl5xDNkwPuA1b1CjJn9cFMqv0JWaMpyGiYLhz//c15UKM9fIz0zhBaz94X+CAvgwmiiWVY1Hs6wcj341IdiFz4TeLIJg42rlNjcZ8FLE14qSApjzJI49DMINxdhEoood/WoG2nJE58c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=FFdezFu4; arc=none smtp.client-ip=209.85.218.67 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FFdezFu4" Received: by mail-ej1-f67.google.com with SMTP id a640c23a62f3a-af8fd1b80e5so83783266b.2; Wed, 06 Aug 2025 18:55:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1754531699; x=1755136499; 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=ujwRlQAOixxVFLF3P3Xei9KX9iGKrNXHg+2EQTVW5iw=; b=FFdezFu4vDoke3zMgaq9jvRR5jLPpVUOG9pIivD40wDUoo2J+zVpEozAcRwwdpnh1N Gr0rlgMSQJCEAGMs/ZyCWTSa6x7bWLXkxbuFjiR/zDkqRpmqiawiCGaR974CR6AYwnMU UiIrtssR/XWr1p5DlB2G3Eu++F5f4fBqF4lLUxRJXdD52k1KUeybN4TekGS/hQ9wq4S+ kKlJDS1HcqyHV3RJlP7JH1iOQk9AkQeOtt3cGq5MuL/c3q3PLp0J8TaYtaHHc+m5VfOs RmH2dMOKYDJtMFS57JebTSYLgxmNZQtoNZYdgkOnBTBxJ8gfUXXdcCt2doHcZRyBEtKX 57QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754531699; x=1755136499; 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=ujwRlQAOixxVFLF3P3Xei9KX9iGKrNXHg+2EQTVW5iw=; b=NLzYIR7xm5kw5MkXXhsfCnAtjPeb9vSwuzWKMKXnjzvFOEUmYt0LOgM9JIQpcxAUpG Bq13VTQ1/BVqJNR7cJFKNywMNHRposzyEu0YN2MDWxBv+Y+k0E9MglDnhE6+l7NxJYyP i1pjj/2BmrUFUuNGYph1va0yeMv1QvQMvqT6TD7hYR6mYswol8pIbOeFnTIMzGD2YQRH DFfyNIoZHVurobQv3+hOdqysSvw1JrgC8SqEVw2W3NYS9Biwpa1Nx8u3fdGB6fMxh9yi SfmaT2WMz4CthPD6dkRAQUixDimdZSgeBoApV8N3/qkzyT7XImDQCyIrwd02u7pLodhO S6qw== X-Forwarded-Encrypted: i=1; AJvYcCUBzJwQJGuM0MKuJtDV10f9VVoLYDQ4kuxtKX6SnIfHWqsb1svdsOBJJusxpPkugm07ZiOdZFh4rzDKOK0=@vger.kernel.org, AJvYcCXOueEfNSDCOWjGlR2oXUhi3MquqBDjSIpMn3swym3Jushn5jAPpTM0pDymLre6TskzjerZ0kmywA1H@vger.kernel.org X-Gm-Message-State: AOJu0YxFpPpj6DFkeqDygpFioyc7wF0xrmp6QbZ1nclZ8Fy2HJ1/2ALy J37E52IHbpuecIc+iy8nKiq3fAI27gozNDdJ2p4u+3D0cu06ZBDxaBjO X-Gm-Gg: ASbGncsvyhIO0feiK/LJtyAsTH8vMzcfSUisk7yw5W4tXkEqXg8zJdrinHE8SXjr2Wl 6UcmZTqd1uRG256umPT+SLCPTprNwabLFsyn1EqyZ3c73TqeD5X9ARpkp5oXvic72TyjTo+YvxT Vp+3/kLQRh6zdDfjZcGje3uqruJEkk5S4yKhA3i2OOQLwMjDMoUq9RE/qHEMHjLctWS229rKbvo r+GLcSD5JDwM4dKXjKcT+jaK4KpGvGJ6WG1cKDhSKnajnuPC4wklf7q367kPtxLV4+pU+0472zB 42bZ6VQfUIoR0CyTPS5Vel/xDccj+1/aAdaEg7nyk23XY0FEcJl/V34NWnLBWrv4gReNqj/h+Fe e8zQWlS+dgLfjmy3D257DIJokxKP6LLSwqV705pPgW8vlp2iYvfzb1RiWpkBpOVRV0hcqC6hHLI N70WHdu2tPTsbVszb4 X-Google-Smtp-Source: AGHT+IHgp4Rd2zyE3rVGDEOZP4X8ktT3n+JKIRK0hV5+AIl4Hb6xONo2Qx5UAqKol8VAGYxnqlw+Wg== X-Received: by 2002:a17:906:dc8d:b0:af3:9676:e9ec with SMTP id a640c23a62f3a-af9903fc6d2mr452862366b.39.1754531698948; Wed, 06 Aug 2025 18:54:58 -0700 (PDT) Received: from [26.26.26.1] (95.112.207.35.bc.googleusercontent.com. [35.207.112.95]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-af91a21c10asm1218337866b.116.2025.08.06.18.54.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 06 Aug 2025 18:54:58 -0700 (PDT) Message-ID: <9d53f097-7e12-4a4c-a2e9-e7b3f2f911a9@gmail.com> Date: Thu, 7 Aug 2025 09:54:51 +0800 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] PCI/DPC: Extend DPC recovery timeout To: Keith Busch , Bjorn Helgaas Cc: Lukas Wunner , Hongbo Yao , Sathyanarayanan Kuppuswamy , bhelgaas@google.com, mahesh@linux.ibm.com, oohall@gmail.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, jemma.zhang@hj-micro.com, peter.du@hj-micro.com References: <20250806213409.GA19037@bhelgaas> Content-Language: en-US From: Ethan Zhao In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/7/2025 5:52 AM, Keith Busch wrote: > On Wed, Aug 06, 2025 at 04:34:09PM -0500, Bjorn Helgaas wrote: >>>> However, the current 4 seconds timeout in pci_dpc_recovered() is indeed >>>> an empirical value rather than a hard requirement from the PCIe >>>> specification. In real-world scenarios, like with Mellanox ConnectX-5/7 >>>> adapters, we've observed that full DPC recovery can take more than 5-6 >>>> seconds, which leads to premature hotplug processing and device removal. >>> >>> I think Sathya's point was: Have you made an effort to talk to the >>> vendor and ask them to root-cause and fix the issue e.g. with a firmware >>> update. >> >> Would definitely be great, but unless we have a number in the spec to >> point to, they might just shrug and ask what the requirement is. > > I agree, and I have similar problems with other arbitrary kernel timing > decicsions. Specifically RRL where there's no spec defined number yet my > patch to modify it has not received much consideration. > > https://lore.kernel.org/linux-pci/20250218165444.2406119-1-kbusch@meta.com/ > At least, with this patch, have a workaround in hand to make some device work. Thanks, Ethan