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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 D6549C432C0 for ; Thu, 21 Nov 2019 20:49:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A90D6206CB for ; Thu, 21 Nov 2019 20:49:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574369368; bh=5De6lyHZUeIRTKocUVUZWotA5hsrs6wr64RApzhHGgI=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=STUjgaW4tL/xdP9LhJWR8cUn6MgZ49wJHA60j7ltocqAsbQnIJr5+je0hzgd54TQY J+s9w4Qh90ijLvUREnubX2VbHbyZ7l7xBMxNOcJ33whPPV6pCTbejjhQOac0+NM3D/ mfJ31qly81DBMsr58qIaQtvLI523ABp0tyRiB8VI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726546AbfKUUt2 (ORCPT ); Thu, 21 Nov 2019 15:49:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:55762 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726293AbfKUUt2 (ORCPT ); Thu, 21 Nov 2019 15:49:28 -0500 Received: from localhost (unknown [69.71.4.100]) (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 6BD242068D; Thu, 21 Nov 2019 20:49:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574369366; bh=5De6lyHZUeIRTKocUVUZWotA5hsrs6wr64RApzhHGgI=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=RxqRR/wsuytn/Fk9HzlloMcfWPyCmZvWj4q5D85e7WnL/HwjE6sSpXaCPt5ezzfHP hx/jsG8D4t+dyh/UgLYDBunGpDfNo6DiRQO9HG1UlrYGlkIXA2O8vSBaqnwpANHKV9 Oqy0KvYY0UM3dpvN+VOgNPO9C1kXgK+k9Abhx2DU= Date: Thu, 21 Nov 2019 14:49:24 -0600 From: Bjorn Helgaas To: Heiner Kallweit Cc: Frederick Lawler , Greg KH , Rajat Jain , linux-pci@vger.kernel.org, "Rafael J. Wysocki" , Mika Westerberg , Wong Vee Khee , Hui Chun Ong , Keith Busch , linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 4/5] PCI/ASPM: Add sysfs attributes for controlling ASPM link states Message-ID: <20191121204924.GA81030@google.com> 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) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Rafael, Mika, Wong, Hui, Rajat, Keith, LKML, original patch at [5]] On Sat, Oct 05, 2019 at 02:07:56PM +0200, Heiner Kallweit wrote: > +What: /sys/bus/pci/devices/.../link_pm/clkpm > + /sys/bus/pci/devices/.../link_pm/l0s_aspm > + /sys/bus/pci/devices/.../link_pm/l1_aspm > + /sys/bus/pci/devices/.../link_pm/l1_1_aspm > + /sys/bus/pci/devices/.../link_pm/l1_2_aspm > + /sys/bus/pci/devices/.../link_pm/l1_1_pcipm > + /sys/bus/pci/devices/.../link_pm/l1_2_pcipm > +Date: October 2019 > +Contact: Heiner Kallweit > +Description: If ASPM is supported for an endpoint, then these files > + can be used to disable or enable the individual > + power management states. Write y/1/on to enable, > + n/0/off to disable. This is queued up for the v5.5 merge window, so if we want to tweak anything (path names or otherwise), now is the time. I think I might be inclined to change the directory from "link_pm" to "link", e.g., - /sys/bus/pci/devices/0000:00:1c.0/link_pm/clkpm + /sys/bus/pci/devices/0000:00:1c.0/link/clkpm because there are other things that haven't been merged yet that could go in link/ as well: * Mika's "link disable" control [1] * Dilip's link width/speed controls [2,3] The max_link_speed, max_link_width, current_link_speed, current_link_width files could also logically be in link/, although they've already been merged at the top level. Rajat's AER statistics change [4] is also coming. Those stats aren't link-related, so they wouldn't go in link/. The current strawman is an "aer_stats" directory, but I wonder if we should make a more generic directory like "errors" that could be used for both AER and DPC and potentially other error-related things. For example, we could have these link-related things: /sys/.../0000:00:1c.0/link/clkpm # RW ASPM stuff /sys/.../0000:00:1c.0/link/l0s_aspm /sys/.../0000:00:1c.0/link/... /sys/.../0000:00:1c.0/link/disable # RW Mika /sys/.../0000:00:1c.0/link/speed # RW Dilip's control /sys/.../0000:00:1c.0/link/width # RW Dilip's control /sys/.../0000:00:1c.0/link/max_speed # RO possible rework /sys/.../0000:00:1c.0/link/max_width # RO possible rework With these backwards compatibility symlinks: /sys/.../0000:00:1c.0/max_link_speed -> link/max_speed /sys/.../0000:00:1c.0/current_link_speed -> link/speed Rajat's current patch puts the AER stats here at the top level: /sys/.../0000:00:1c.0/aer_stats/fatal_bit4_DLP But maybe we could push them down like this: /sys/.../0000:00:1c.0/errors/aer/stats/unc_04_dlp /sys/.../0000:00:1c.0/errors/aer/stats/unc_26_poison_tlb_blocked /sys/.../0000:00:1c.0/errors/aer/stats/cor_00_rx_err /sys/.../0000:00:1c.0/errors/aer/stats/cor_15_hdr_log_overflow There are some AER-related things we don't have at all today that could go here: /sys/.../0000:00:1c.0/errors/aer/ecrc_gen /sys/.../0000:00:1c.0/errors/aer/ecrc_check /sys/.../0000:00:1c.0/errors/aer/unc_err_status /sys/.../0000:00:1c.0/errors/aer/unc_err_mask /sys/.../0000:00:1c.0/errors/aer/unc_err_sev And we might someday want DPC knobs like this: /sys/.../0000:00:1c.0/errors/dpc/status /sys/.../0000:00:1c.0/errors/dpc/error_source Any thoughts? Bjorn [1] https://lore.kernel.org/r/20190529104942.74991-1-mika.westerberg@linux.intel.com [2] https://lore.kernel.org/r/d8574605f8e70f41ce1e88ccfb56b63c8f85e4df.1571638827.git.eswara.kota@linux.intel.com [3] https://lore.kernel.org/r/20191030221436.GA261632@google.com/ [4] https://lore.kernel.org/r/20190827222145.32642-2-rajatja@google.com [5] https://lore.kernel.org/r/b1c83f8a-9bf6-eac5-82d0-cf5b90128fbf@gmail.com