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 C54F2C4332F for ; Thu, 14 Dec 2023 17:28:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230018AbjLNR2q (ORCPT ); Thu, 14 Dec 2023 12:28:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229464AbjLNR2o (ORCPT ); Thu, 14 Dec 2023 12:28:44 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6072A121 for ; Thu, 14 Dec 2023 09:28:50 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF9B0C433C9; Thu, 14 Dec 2023 17:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702574930; bh=P8WIww2274+m+ez0eGWOb23W8iwkilWxoapMNkXmSoI=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=XSEj/glB2zBkw6SiLPvUtM7upEYS6XnUikmteJZhAXnZflzbW9uW2qbKlLuj8JaR3 UhCXpC+lFeRGOw1IH9McsmcQIHs88KaO0Zm++1VMWO0glWqQbsdtsF9It0QV/TVoeK tizuaDJFXwxG+GqeCFsx5zJVqjTyuJt7syIyQXYW+tgvVRDUw022BVmN4duObs3PK0 gx3rV4ogqff+iZhJ3WSTWwtSNdqoH8GuBE9oNeW9qYcb7dHFDqtBzlcgFPhTQOu9um BUFF59MaswASLf/oCfWgvWtd1L4cH6+ERTkVa6W5wGNh642111BGBanJ0MsJQLXH4g QX8Sj6bAewScw== Date: Thu, 14 Dec 2023 11:28:48 -0600 From: Bjorn Helgaas To: "David E. Box" Cc: Kai-Heng Feng , Johan Hovold , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Bjorn Helgaas , Andy Gross , Bjorn Andersson , Konrad Dybcio , Manivannan Sadhasivam , Rob Herring , Nirmal Patel , Jonathan Derrick , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Manivannan Sadhasivam Subject: Re: [PATCH v2 1/6] PCI/ASPM: Add locked helper for enabling link state Message-ID: <20231214172848.GA1095194@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 13, 2023 at 03:39:24PM -0800, David E. Box wrote: > On Wed, 2023-12-13 at 14:45 -0600, Bjorn Helgaas wrote: > ... > > I'd be shocked if Windows treated the BIOS config as a "do not exceed > > this" situation, so my secret hope is that some of these "broken" > > devices are really caused by defects in the Linux ASPM support or the > > driver, and that we can fix them if we find out about them. > > > > But I have no details about any of these alleged broken devices, so > > it's hard to make progress on them.   > > I don't have a sense of the scope either. But I could see BIOS not > enabling features that would provide no added power savings benefit. > We use ASPM to manage package power. There are Intel devices that > certainly don't require L1SS for the SoC to achieve the deepest > power savings. L1 alone is fine for them. I don't know what the test > coverage is for unenabled features. I've sent these questions to > our BIOS folks. Once upon a time there was a push to make it so firmware only had to enumerate boot and console devices and it could skip enumeration and configuration of other devices. But I don't think we've made much progress on that, at least for x86, possibly because Linux depends so much on BIOS resource assignment. IMO that's a Linux deficiency. Bjorn