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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D450AEB64D7 for ; Fri, 16 Jun 2023 22:01:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231690AbjFPWBb (ORCPT ); Fri, 16 Jun 2023 18:01:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229952AbjFPWBa (ORCPT ); Fri, 16 Jun 2023 18:01:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8379D297E; Fri, 16 Jun 2023 15:01:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B5F9A61F51; Fri, 16 Jun 2023 22:01:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7494C433C8; Fri, 16 Jun 2023 22:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686952888; bh=lor+9CzJuJ16UAG83X/TrSjJxGuaeIWyzZ4JuzMH5fQ=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=lZPkTGzs39ZHNiZkaoRWItQiE0QwvxE957VSI9JWquQq4mV90qHPQptOpsBAx+lze xfiHf2HcLRwfopB8TRTD6qhV4NHGBjs+mtLNFejEWYk0sl6RIxowOwbXT8GJzlivg8 wpw+MI/FVXVsuxy1n3sqLrOSjqD4HsBX/hbU20KB0vepY8onDtXm4vyrajS0dcR8Ub th22LqZDDA1LOI55A6huIW9/QZ9MeQc6sptqeKTvTdZON67TGfxJdxH+QJH1tGssol +Whion7zGtqqG5VJbz9TjDVzpYXZ/t8hvrEUMtynD+jz9KQw69B6w3xNw4N7TxLMAP naFyJtKNzxD4w== Date: Fri, 16 Jun 2023 17:01:25 -0500 From: Bjorn Helgaas To: Kai-Heng Feng Cc: bhelgaas@google.com, Mario Limonciello , Mika Westerberg , Kuppuswamy Sathyanarayanan , Vidya Sagar , Michael Bottini , "Rafael J. Wysocki" , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI/ASPM: Enable ASPM on external PCIe devices Message-ID: <20230616220125.GA1555182@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230615070421.1704133-1-kai.heng.feng@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jun 15, 2023 at 03:04:20PM +0800, Kai-Heng Feng wrote: > When a PCIe device is hotplugged to a Thunderbolt port, ASPM is not > enabled for that device. However, when the device is plugged preboot, > ASPM is enabled by default. > > The disparity happens because BIOS doesn't have the ability to program > ASPM on hotplugged devices. > > So enable ASPM by default for external connected PCIe devices so ASPM > settings are consitent between preboot and hotplugged. > > On HP Thunderbolt Dock G4, enable ASPM can also fix BadDLLP error: > pcieport 0000:00:1d.0: AER: Corrected error received: 0000:07:04.0 > pcieport 0000:07:04.0: PCIe Bus Error: severity=Corrected, type=Data Link Layer, (Receiver ID) > pcieport 0000:07:04.0: device [8086:0b26] error status/mask=00000080/00002000 > pcieport 0000:07:04.0: [ 7] BadDLLP > > The root cause is still unclear, but quite likely because the I225 on > the dock supports PTM, where ASPM timing is precalculated for the PTM. > Link: https://bugzilla.kernel.org/show_bug.cgi?id=217557 I know you said this isn't clear yet, but I don't see a connection between ASPM being enabled and PTM. If anything, *disabling* ASPM should be safer if there's a timing issue. I assume the ASPM timing you refer to is the LTR snoop/no snoop latency, since that's the only timing difference I see in the lspci output in bugzilla? I don't see any PTM differences there. Bjorn