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=-8.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 C13AAC43219 for ; Thu, 25 Apr 2019 15:32:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7A0A206C0 for ; Thu, 25 Apr 2019 15:32:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="u3lROnbm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729981AbfDYPcy (ORCPT ); Thu, 25 Apr 2019 11:32:54 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:43080 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729901AbfDYPcv (ORCPT ); Thu, 25 Apr 2019 11:32:51 -0400 Received: by mail-pl1-f196.google.com with SMTP id n8so11268203plp.10; Thu, 25 Apr 2019 08:32:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7iW4MbVd77MEAccCwSku/MkHI3UfK1BuasUTDy15CeE=; b=u3lROnbm0VN76si2ABD4XoHYOXl2xIcsMsmytLpSxXYVKKCC+htJeY8bTEPD/S3Phe UNoWAEeO8B8FO969vE0Hl8R+qas+OT0BcPFzY2kEuAIQ4ZkY3ydS7Jr5lSuB1jD3DEE6 OUBy5sU/S3rSxjGDBD7JSbfl9pfde3FToAjtmDjcjfcQeElSRUOdCK5iJDnuM9aoRPRW 9iO+wcAuC7s9EKBsnLX65eAdj7/y6z9xaAerkUY8BVylQeGubiIw6/8Ebg+1yGyCigYB 8BctT4BfoeHJt8Ab04al19rVcTfxHYwrfzz9wWNlJjN+SN5ut9DYi782wGk3EzYcV1E/ x9eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=7iW4MbVd77MEAccCwSku/MkHI3UfK1BuasUTDy15CeE=; b=h/aNhATwDwhk6H0zs6a/nX//Gw4KcTFUTz59ZvhiKB/g5QN3ymqvmafaFR9itBdsi3 WR3KPJb7UHvX/WduGWzdvE4iJ0Tl+Vv8Jm9+lsSv4NvmrmlKBsuQuoF/VAA2L3yp78f+ h5lJjyh8elMypzcy6cvKUJGoH2IZOteagYTfiq/AAfEx3gTHl1jg8Ac/PaYu+oV0EyZw XwxFkmZxH+J6tAieMkzOYArAsXl2wLzwcKgMhTy4tuIc6yL4gjJ39AoB6ZiYuyb6+dBs pTzWVPt//Yl3d+8n0b0OuFsSBynPTLKsqQxushdJ6ZbQuQlWCFwicQAk3/TZ4Mh3qN6k Igrw== X-Gm-Message-State: APjAAAXWMLBvXqFaOB7BBe+EtK3EawWpc9SkaytZENfs25OqcGpAgqet h5+M8sXacipXGGldV4yZF5w= X-Google-Smtp-Source: APXvYqwatzTfNnv6S1Wgdobw7qtMufyuTFu57h2iiajodT0TTyLGILlwrVsoBD8jHQDyecaxVxCO0Q== X-Received: by 2002:a17:902:968b:: with SMTP id n11mr39637747plp.118.1556206370992; Thu, 25 Apr 2019 08:32:50 -0700 (PDT) Received: from localhost.localdomain ([104.238.181.70]) by smtp.gmail.com with ESMTPSA id c14sm2643363pgj.94.2019.04.25.08.32.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Apr 2019 08:32:50 -0700 (PDT) From: Changbin Du To: rjw@rjwysocki.net, Jonathan Corbet Cc: Bjorn Helgaas , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, fenghua.yu@intel.com, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-gpio@vger.kernel.org, mchehab+samsung@kernel.org, Changbin Du Subject: [PATCH v6 13/24] Documentation: ACPI: move acpi-lid.txt to firmware-guide/acpi and convert to reST Date: Thu, 25 Apr 2019 23:31:06 +0800 Message-Id: <20190425153117.16057-14-changbin.du@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190425153117.16057-1-changbin.du@gmail.com> References: <20190425153117.16057-1-changbin.du@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du Reviewed-by: Mauro Carvalho Chehab --- .../acpi/acpi-lid.rst} | 40 ++++++++++++++----- Documentation/firmware-guide/acpi/index.rst | 1 + 2 files changed, 30 insertions(+), 11 deletions(-) rename Documentation/{acpi/acpi-lid.txt => firmware-guide/acpi/acpi-lid.rst} (86%) diff --git a/Documentation/acpi/acpi-lid.txt b/Documentation/firmware-guide/acpi/acpi-lid.rst similarity index 86% rename from Documentation/acpi/acpi-lid.txt rename to Documentation/firmware-guide/acpi/acpi-lid.rst index effe7af3a5af..874ce0ed340d 100644 --- a/Documentation/acpi/acpi-lid.txt +++ b/Documentation/firmware-guide/acpi/acpi-lid.rst @@ -1,13 +1,18 @@ -Special Usage Model of the ACPI Control Method Lid Device +.. SPDX-License-Identifier: GPL-2.0 +.. include:: -Copyright (C) 2016, Intel Corporation -Author: Lv Zheng +========================================================= +Special Usage Model of the ACPI Control Method Lid Device +========================================================= +:Copyright: |copy| 2016, Intel Corporation -Abstract: +:Author: Lv Zheng -Platforms containing lids convey lid state (open/close) to OSPMs using a -control method lid device. To implement this, the AML tables issue +Abstract +======== +Platforms containing lids convey lid state (open/close) to OSPMs +using a control method lid device. To implement this, the AML tables issue Notify(lid_device, 0x80) to notify the OSPMs whenever the lid state has changed. The _LID control method for the lid device must be implemented to report the "current" state of the lid as either "opened" or "closed". @@ -19,7 +24,8 @@ taken into account. This document describes the restrictions and the expections of the Linux ACPI lid device driver. -1. Restrictions of the returning value of the _LID control method +Restrictions of the returning value of the _LID control method +============================================================== The _LID control method is described to return the "current" lid state. However the word of "current" has ambiguity, some buggy AML tables return @@ -30,7 +36,8 @@ initial returning value. When the AML tables implement this control method with cached value, the initial returning value is likely not reliable. There are platforms always retun "closed" as initial lid state. -2. Restrictions of the lid state change notifications +Restrictions of the lid state change notifications +================================================== There are buggy AML tables never notifying when the lid device state is changed to "opened". Thus the "opened" notification is not guaranteed. But @@ -39,18 +46,22 @@ state is changed to "closed". The "closed" notification is normally used to trigger some system power saving operations on Windows. Since it is fully tested, it is reliable from all AML tables. -3. Expections for the userspace users of the ACPI lid device driver +Expections for the userspace users of the ACPI lid device driver +================================================================ The ACPI button driver exports the lid state to the userspace via the -following file: +following file:: + /proc/acpi/button/lid/LID0/state + This file actually calls the _LID control method described above. And given the previous explanation, it is not reliable enough on some platforms. So it is advised for the userspace program to not to solely rely on this file to determine the actual lid state. The ACPI button driver emits the following input event to the userspace: - SW_LID + * SW_LID + The ACPI lid device driver is implemented to try to deliver the platform triggered events to the userspace. However, given the fact that the buggy firmware cannot make sure "opened"/"closed" events are paired, the ACPI @@ -59,20 +70,25 @@ button driver uses the following 3 modes in order not to trigger issues. If the userspace hasn't been prepared to ignore the unreliable "opened" events and the unreliable initial state notification, Linux users can use the following kernel parameters to handle the possible issues: + A. button.lid_init_state=method: When this option is specified, the ACPI button driver reports the initial lid state using the returning value of the _LID control method and whether the "opened"/"closed" events are paired fully relies on the firmware implementation. + This option can be used to fix some platforms where the returning value of the _LID control method is reliable but the initial lid state notification is missing. + This option is the default behavior during the period the userspace isn't ready to handle the buggy AML tables. + B. button.lid_init_state=open: When this option is specified, the ACPI button driver always reports the initial lid state as "opened" and whether the "opened"/"closed" events are paired fully relies on the firmware implementation. + This may fix some platforms where the returning value of the _LID control method is not reliable and the initial lid state notification is missing. @@ -80,6 +96,7 @@ B. button.lid_init_state=open: If the userspace has been prepared to ignore the unreliable "opened" events and the unreliable initial state notification, Linux users should always use the following kernel parameter: + C. button.lid_init_state=ignore: When this option is specified, the ACPI button driver never reports the initial lid state and there is a compensation mechanism implemented to @@ -89,6 +106,7 @@ C. button.lid_init_state=ignore: notifications can be delivered to the userspace when the lid is actually opens given that some AML tables do not send "opened" notifications reliably. + In this mode, if everything is correctly implemented by the platform firmware, the old userspace programs should still work. Otherwise, the new userspace programs are required to work with the ACPI button driver. diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst index 1c89888f6ee8..bedcb0b242a2 100644 --- a/Documentation/firmware-guide/acpi/index.rst +++ b/Documentation/firmware-guide/acpi/index.rst @@ -14,3 +14,4 @@ ACPI Support DSD-properties-rules gpio-properties i2c-muxes + acpi-lid \ No newline at end of file -- 2.20.1