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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C3491C10F14 for ; Thu, 3 Oct 2019 15:58:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 995B0207FF for ; Thu, 3 Oct 2019 15:58:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570118309; bh=wKhq0VlGv+xSfbaRl9RM2mr581f4Gr7wpu/qX6+fz9s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pyQSaVe9Vlj/+oBf5mbammmxuyRKML5hVfsY8rURuWHQGYjCxlZ/+q1Yldi3BQX9R 6qXjWMZpxwS/vncFfO5379Ok0x/cFUgnuvUSL5MlChRx5htgk4H3FDTxKH3Nbk8Jal LIJiN81dFv1y3KUzuQdYNcIeYBek0joE0NP74POI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731226AbfJCP62 (ORCPT ); Thu, 3 Oct 2019 11:58:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:41116 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731129AbfJCP6Y (ORCPT ); Thu, 3 Oct 2019 11:58:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 9CCE321A4C; Thu, 3 Oct 2019 15:58:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570118303; bh=wKhq0VlGv+xSfbaRl9RM2mr581f4Gr7wpu/qX6+fz9s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q/O8snOPOnSwXgWYd/ddGXrx+mjdXkf9B03/ZcfPhQYJjVwVIJoNmOdus/jkMB3yN VWsbQ5QRb4rUvakpWCGnsVB6UxqIfefiEKzAuWq+GjHcFttYcaP6Kl/kXxpDqTCev6 iD54hH+ePsgPfPy2S95mpqQP3IaWcR6mCVNulJNQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Stone , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 4.4 62/99] ACPI / CPPC: do not require the _PSD method Date: Thu, 3 Oct 2019 17:53:25 +0200 Message-Id: <20191003154326.977690200@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154252.297991283@linuxfoundation.org> References: <20191003154252.297991283@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Al Stone [ Upstream commit 4c4cdc4c63853fee48c02e25c8605fb65a6c9924 ] According to the ACPI 6.3 specification, the _PSD method is optional when using CPPC. The underlying assumption is that each CPU can change frequency independently from all other CPUs; _PSD is provided to tell the OS that some processors can NOT do that. However, the acpi_get_psd() function returns ENODEV if there is no _PSD method present, or an ACPI error status if an error occurs when evaluating _PSD, if present. This makes _PSD mandatory when using CPPC, in violation of the specification, and only on Linux. This has forced some firmware writers to provide a dummy _PSD, even though it is irrelevant, but only because Linux requires it; other OSPMs follow the spec. We really do not want to have OS specific ACPI tables, though. So, correct acpi_get_psd() so that it does not return an error if there is no _PSD method present, but does return a failure when the method can not be executed properly. This allows _PSD to be optional as it should be. Signed-off-by: Al Stone Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/cppc_acpi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c index 0afd1981e350b..43c27c04c40ae 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -137,8 +137,10 @@ static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle) union acpi_object *psd = NULL; struct acpi_psd_package *pdomain; - status = acpi_evaluate_object_typed(handle, "_PSD", NULL, &buffer, - ACPI_TYPE_PACKAGE); + status = acpi_evaluate_object_typed(handle, "_PSD", NULL, + &buffer, ACPI_TYPE_PACKAGE); + if (status == AE_NOT_FOUND) /* _PSD is optional */ + return 0; if (ACPI_FAILURE(status)) return -ENODEV; -- 2.20.1