From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48CB1C433E4 for ; Thu, 23 Jul 2020 01:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 294EB2086A for ; Thu, 23 Jul 2020 01:04:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595466281; bh=vuI1DM19pqZiO1W8ggE5LH1WTZ2Zpcgqkw+bo5G96Ck=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=y2V+PEqhE0YMRKbLhIILKtzpKKDyuO3BFj2x8f3vO6c1Yj17CtGrdRUBYEJJF2Nu0 tlxeYMCDJ3m6bVoh/cEfrDt0YddFaGZWPhQ9iUIRj6FepoKFQSzdQuVa1RZtP1pVsm otrH9BWtlsaA9DPTE9F1JYdcnPqLqAWzeKUrlolk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387537AbgGWBEi (ORCPT ); Wed, 22 Jul 2020 21:04:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:51412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733221AbgGWBEi (ORCPT ); Wed, 22 Jul 2020 21:04:38 -0400 Received: from localhost (mobile-166-175-191-139.mycingular.net [166.175.191.139]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2304A2086A; Thu, 23 Jul 2020 01:04:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595466277; bh=vuI1DM19pqZiO1W8ggE5LH1WTZ2Zpcgqkw+bo5G96Ck=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=MpOL3ZEwKycICyUmrC1pWvUtYaPqBRrm/poJm+Ttw+ilyCs2OunPnbiK0/+5wn6GA iSX9250ee4qncolPYrWXRTazw378B+mZOYLVwC6ST85WE6hdohzUUcDhbCzYnSjxVD 7+Q7zIhhuaxjOKax49rs2eFqF0bQfD3akrbJvs1o= Date: Wed, 22 Jul 2020 20:04:35 -0500 From: Bjorn Helgaas To: Robert Hancock Cc: linux-pci@vger.kernel.org, linux-kernel , Bjorn Helgaas , stable@vger.kernel.org, Puranjay Mohan Subject: Re: [PATCH] PCI: Disallow ASPM on ASMedia ASM1083/1085 PCIe-PCI bridge Message-ID: <20200723010435.GA1334095@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jul 22, 2020 at 06:46:06PM -0600, Robert Hancock wrote: > On Wed, Jul 22, 2020 at 11:40 AM Bjorn Helgaas wrote: > > On Tue, Jul 21, 2020 at 08:18:03PM -0600, Robert Hancock wrote: > > > Recently ASPM handling was changed to no longer disable ASPM on all > > > PCIe to PCI bridges. Unfortunately these ASMedia PCIe to PCI bridge > > > devices don't seem to function properly with ASPM enabled, as they > > > cause the parent PCIe root port to cause repeated AER timeout errors. > > > In addition to flooding the kernel log, this also causes the machine > > > to wake up immediately after suspend is initiated. > > > > Hi Robert, thanks a lot for the report of this problem > > (https://lore.kernel.org/r/CADLC3L1R2hssRjxHJv9yhdN_7-hGw58rXSfNp-FraZh0Tw+gRw@mail.gmail.com > > and https://bugzilla.redhat.com/show_bug.cgi?id=1853960). > > > > I'm pretty sure Linux ASPM support is missing some things. This > > problem might be a hardware problem where a quirk is the right > > solution, but it could also be that it's a result of a Linux defect > > that we should fix. > > > > Could you collect the dmesg log and "sudo lspci -vvxxxx" output > > somewhere (maybe a bugzilla.kernel.org issue)? I want to figure out > > whether this L1 PM substates are enabled on this link, and whether > > that's configured correctly. > > Created a Bugzilla entry and added dmesg and lspci output: > https://bugzilla.kernel.org/show_bug.cgi?id=208667 > > As I noted in that report, I subsequently found this page on ASMedia's > site: https://www.asmedia.com.tw/eng/e_show_products.php?cate_index=169&item=114 > which indicates this ASM1083 device has "No PCIe ASPM support". How nice. According to your lspci, the device itself claims to support ASPM: 02:00.0 ... ASMedia Technology Inc. ASM1083/1085 PCIe to PCI Bridge LnkCap: ... ASPM L0s L1 ... but the web page claims otherwise. That would mean the device is defective for claiming something that's not true. Or possibly those capability bits can be set by BIOS. > It's not clear why this problem isn't occurring on Windows however - > either it is not enabling ASPM, somehow it doesn't cause issues with > the PCIe link, or it is causing issues and just doesn't notify the > user in any way. I can try and check if this bridge device is ending > up with ASPM enabled under Windows 10 or not.. If Windows *does* manage to enable ASPM, that would be interesting. I don't know whether Windows has a similar quirk mechanism. I suppose they must have *some* way to work around defective devices. Bjorn