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 4C061C4332F for ; Fri, 10 Nov 2023 18:24:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345433AbjKJSYz (ORCPT ); Fri, 10 Nov 2023 13:24:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37070 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345765AbjKJSXx (ORCPT ); Fri, 10 Nov 2023 13:23:53 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B98923975C; Fri, 10 Nov 2023 06:39:03 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0380EC433C7; Fri, 10 Nov 2023 14:39:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1699627143; bh=s66gHHjMySKSZbn63cKJJA1Bvs2R0xW/wRdb8aMe4VM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=VFN97HdpzS3TdmFDybUTeRVCW09lhWWC4tRqyIS+CJOfjgUOb1/QZsUqBsh3Faud+ 8/VXIg+r7JgsdtSQWbNI2dCwUuSNis7hCZ33JkThOLGRHDkoGeIPItVjODWGpXGlAN e6htKbqPWQndkLiBSKa9sBfFQ/WvtOKbM81ZhJZTXZGfQzp3IIbfkgytF88bTCD2E1 WEahUa7JQGdec/XKOTdqLY2Nt9mBw1QeII28O3HYEF3X4JUDc76LlLvvXbfIe9ZxJ4 z++kez5RnEOipVViYdFHeoIgvWNLwwBN8Ux9Yha2VY9K+lV8BXD9edSHk8hgkbXiMO cHYbRBuQqKKow== Date: Fri, 10 Nov 2023 08:39:01 -0600 From: Bjorn Helgaas To: Jim Quinlan Cc: linux-pci@vger.kernel.org, Nicolas Saenz Julienne , Bjorn Helgaas , Lorenzo Pieralisi , Cyril Brulebois , Phil Elwell , bcm-kernel-feedback-list@broadcom.com, Jim Quinlan , Florian Fainelli , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" , open list Subject: Re: [PATCH v7 2/3] PCI: brcmstb: Configure HW CLKREQ# mode appropriate for downstream device Message-ID: <20231110143901.GA540912@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-pci@vger.kernel.org On Fri, Nov 10, 2023 at 08:01:23AM -0500, Jim Quinlan wrote: > On Thu, Nov 9, 2023 at 5:31 PM Bjorn Helgaas wrote: > > > > On Thu, Nov 09, 2023 at 05:06:15PM -0500, Jim Quinlan wrote: > > > ... > > > > > BTW, besides the RPi4, I haven't been able to find a Linux platform > > > where I can do > > > > > > echo $POLICY > /sys/module/pcie_aspm/parameters/policy > > > > This sounds like something we should fix. What exactly happens? I > > think this should be handled at pcie_aspm_set_policy(), so: > > Well, I've tried changing the ASPM policy on my x86 Ubuntu system > and IIRC a Fedora system. In both cases it says "illegal write > operation" but I am root and the "policy" file does have rw perms > for root, so I have no idea how it comes back with that error. Some > machines allow one to change the setting in the BIOS, FWIW. BIOS settings like that are potentially misleading unless the BIOS *also* retains ownership of ASPM or changes the ASPM features advertised by devices. If BIOS grants ASPM ownership to the OS, BIOS should not assume anything about how the OS will configure ASPM. > Right now on my CM4, "echo $POLICY > policy" actually works. > Perhaps when I was testing this I did not yet apply my commits, or > perhaps it was with a specific endpoint device. Regardless, I'll > let you know with a backtrace if I see this again. Great, thanks! Bjorn