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 DE5132BE7C3 for ; Wed, 8 Oct 2025 16:53:47 +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=1759942429; cv=none; b=JJQWF5IkaFnXKi7nNqtM9lvM/WEJ2FAUxDIQSVrnVCvKfqsswZOQn0Ql+zuLcqvbzJxm2d5/SofwTwRuU7pc3qO0A3GRYlmd1DzsakAHSA/d6Dp/pe2D33XyB3Bs8ZVcgBgwzFqeyaEMcClaZ9r0WucTyYRs7HO5d+sW2qX7HvA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759942429; c=relaxed/simple; bh=ax0LWZM9J1kHeBNaFbfBnu/IapGbJsY3j062UFsnR6U=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=XCustYpFuIsLx9Gh+eAioBDlWG+8CQE75Fp9KWQbLvgFT7P6gcPGEA2+dAKWczXEqHoMDUo+jiCBvPAz7WVJL8vhOpK6Mby+tFm91KtJxHC0qQ0mHO9ZaiGVFIF8ZlOuVZ8uyyUcrVss+/Q8m408cSWo13CTeqNMYz24nB8wn+I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pcd+Zt2Z; 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="pcd+Zt2Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45FD2C4CEE7; Wed, 8 Oct 2025 16:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759942427; bh=ax0LWZM9J1kHeBNaFbfBnu/IapGbJsY3j062UFsnR6U=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=pcd+Zt2ZTjI92Bg3DjFOatrYu7fI7mPXMs2cQPobPwbp0QiGaB6SiWXyz5aOciMLn I+xts5QNvbe6CTpDDDqAOwPhZVPPzkWOLyOAsWdzNIgy42wuR/n6tZ7onZi+dIXiIf WMy6pKs4DsvVY52F9JeiBib9/L9AWEVFApUQAZfUDlnDBscfDETlpdciyavEKQGEwz xQENC9hOHQbVK8wWsWFH85Fv5ajbu+Zjf0f2MQeTpJQw8Gg31QKJXy/hyLq0mkvVto Q6YMfsUg2Tzqm0a1bm3dA2NydiXdaGH+oJT8vDGuu5GrTS1+l6RTrzQ7ftlP1uJTNY 0hhgM6pum9Mlw== Date: Wed, 8 Oct 2025 11:53:45 -0500 From: Bjorn Helgaas To: Hui Wang , Nirmal Patel , Jonathan Derrick Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, raphael.norwitz@nutanix.com, alay.shah@nutanix.com, suresh.gumpula@nutanix.com, ilpo.jarvinen@linux.intel.com, Chaitanya Kumar Borah , Ville =?utf-8?B?U3lyasOkbMOk?= Subject: Re: [PATCH] PCI: Disable RRS polling for Intel SSDPE2KX020T8 nvme Message-ID: <20251008165345.GA627277@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250821163936.GA681451@bhelgaas> Nirmal, Jonathan, can you confirm that when RRS SV is enabled for VMD Root Ports, we should actually see the 0x0001 value when a device downstream of VMD responds with RRS? From the log below, it appears that we actually get 0xffffffff when reading Device ID after a reset. On Thu, Aug 21, 2025 at 11:39:36AM -0500, Bjorn Helgaas wrote: > On Thu, Jul 03, 2025 at 08:05:05AM +0800, Hui Wang wrote: > > On 7/2/25 17:43, Hui Wang wrote: > > > On 7/2/25 07:23, Bjorn Helgaas wrote: > ... > > > > Thank you!  It seems like we get 0xffffffff (probably PCIe error) for > > > > a long time after we think the device should be able to respond with > > > > RRS. > > > > > > > > I always thought the spec required that after the delays, a device > > > > should respond with RRS if it's not ready, but now I guess I'm not > > > > 100% sure.  Maybe it's allowed to just do nothing, which would lead to > > > > the Root Port timing out and logging an Unsupported Request error. > > > > > > > > Can I trouble you to try the patch below?  I think we might have to > > > > start explicitly checking for that error.  That probably would require > > > > some setup to enable the error, check for it, and clear it.  I hacked > > > > in some of that here, but ultimately some of it should go elsewhere. > ... The patch is here: https://lore.kernel.org/r/20250701232341.GA1859056@bhelgaas and the log with that patch is here: > > This is the testing result and log. > > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2111521/comments/65 > We're waiting for 01:00.0, and we're seeing the poll message for about > 375 ms: [ 10.177356] pci 10000:00:02.0: PCI bridge to [bus 01] [ 10.182278] pci 10000:01:00.0: [8086:0a54] type 00 class 0x010802 PCIe Endpoint [ 10.195247] pci 10000:00:02.0: pci_reset_secondary_bus: PCI_BRIDGE_CTL_BUS_RESET deasserted [ 10.195464] pci 10000:00:02.0: waiting 100 ms for downstream link, after activation [ 10.195467] pci 10000:00:02.0: pcie_wait_for_link_delay: active 1 delay 100 link_active_reporting 1 [ 10.229269] pci 10000:00:02.0: pcie_wait_for_link_status: LNKSTA 0xb043 [ 10.334784] pci 10000:00:02.0: pcie_wait_for_link_delay: waited 100ms > [ 10.334786] pci 10000:01:00.0: pci_dev_wait: VF- bus reset timeout 59900 > [ 10.334792] pci 10000:00:02.0: pci_dev_wait: read 0xffffffff DEVSTA 0x0000 > ... > [ 10.708367] pci 10000:00:02.0: pci_dev_wait: read 0xffffffff DEVSTA 0x0000 > > The 00:02.0 Root Port has RRS SV enabled, but the config reads of the > 01:00.0 Vendor ID did not return the RRS value (0x0001). Instead, > they returned 0xffffffff, which typically means an error on PCIe.