From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8C77C1E5B88; Wed, 6 Aug 2025 21:52:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754517150; cv=none; b=t+9z9HdqC1q3TsqGwXPhh7sUkiy39UH2jH674PATOA6gVufn75Sd97J0T1DAOhhQIlJdKH7T0VWgVwV+oGVCgm+P4lnApshANn/nbZpbFVF4szbI3V0duxFszR73jIx2zFJLPEYfILQbpvWVVK7BjBNa+fc1SGrTicfmMHtk6BQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754517150; c=relaxed/simple; bh=T0eitd60fDJRGs9O0BFk1ub1fCf0+D8W5+IKuaDejwo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Biu+qHC4qupt/17oiLZ9wsEoUzCKABLa51xBgoJtId4jD90pHHl0LRsWZ5isj/sDieRV4ISYm86xz480Ek0vyJXxdQfcrUXq9rVC2ojN+N+WO4QrnNLm5uuQ67esG8t6vcTMgOTeNeB7c0AQ3Eh6JgiSBho8OeIhdc/zpESGm6c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DTNl1MEG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DTNl1MEG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 628CEC4CEE7; Wed, 6 Aug 2025 21:52:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754517150; bh=T0eitd60fDJRGs9O0BFk1ub1fCf0+D8W5+IKuaDejwo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DTNl1MEGWsAdp8Vvj2gAMfCMRW13XzWTPSGRugZh7JXJXCfZToMb3ktraA4qn1W32 2iV45QpnzV0UmjYR3dooM+A+4JV3HWU2KknmgpetavTqOrzRcqhvEydiisdMEWKZgo nrQqfu0ajHTfAX1OG4hOye5Iv805Mn9MDSthtAq/0ioNszit+Fdgx8TVmBB4ySgdvc ETGsS5dgmhpgOJL99ijo7ajrdYXE7yuyLIwdaQ76whzjegkflNS08AYYiPS7n0RVMY nhHmCUPwkKPvL8ILTVlyOEH4T8GZ1WzhDmH3zYTfGQ2MmE/G8rSFzzqqUW5zs21Avi PKbdUa7RtnsZA== Date: Wed, 6 Aug 2025 15:52:27 -0600 From: Keith Busch To: 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 Subject: Re: [PATCH] PCI/DPC: Extend DPC recovery timeout Message-ID: References: <20250806213409.GA19037@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250806213409.GA19037@bhelgaas> 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/