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 9F673C433EF for ; Thu, 14 Jul 2022 05:06:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231570AbiGNFG1 (ORCPT ); Thu, 14 Jul 2022 01:06:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232847AbiGNFGD (ORCPT ); Thu, 14 Jul 2022 01:06:03 -0400 X-Greylist: delayed 329 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 13 Jul 2022 22:01:47 PDT Received: from cavan.codon.org.uk (irc.codon.org.uk [IPv6:2a00:1098:84:22e::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4B9F1D0D6 for ; Wed, 13 Jul 2022 22:01:47 -0700 (PDT) Received: by cavan.codon.org.uk (Postfix, from userid 1000) id 0558340A56; Thu, 14 Jul 2022 05:56:13 +0100 (BST) Date: Thu, 14 Jul 2022 05:56:13 +0100 From: Matthew Garrett To: Kai-Heng Feng Cc: Bjorn Helgaas , Manyi Li , bhelgaas@google.com, refactormyself@gmail.com, kw@linux.com, rajatja@google.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Vidya Sagar Subject: Re: [PATCH] PCI/ASPM: Should not report ASPM support to BIOS if FADT indicates ASPM is unsupported Message-ID: <20220714045613.GA8720@srcf.ucam.org> References: <20220713112612.6935-1-limanyi@uniontech.com> <20220713182852.GA841582@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jul 14, 2022 at 11:20:26AM +0800, Kai-Heng Feng wrote: > According to commit 387d37577fdd ("PCI: Don't clear ASPM bits when the > FADT declares it's unsupported"), the bit means "just use the ASPM Yes, the assumption is that if the BIOS set up ASPM but FADT indicates it's unsupported, just trust that the BIOS did the right thing and don't interfere. It's been a long time, but when we were clearing the ASPM bits in response to this FADT setting, a bunch of machines suddenly started consuming a lot more power than when running Windows.