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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 1A4E1C4740C for ; Sun, 22 Sep 2019 19:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E7DD420869 for ; Sun, 22 Sep 2019 19:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569179771; bh=K0AEGtS3ru3m5o3GBWv+/gtrDrzTVL4cNuryvWAlht0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eieBtGlBsmyDQEYHDFNVXHW70bDQeCWHpfnU6Ye6P14VKHbiohzo3BAerbKk/1CC1 H4LBoW7S/gXLlL/aNtZNfBBVjQqbeLXpKtsyroALbsb0VLTSuly29cwJ/ZAQSqYFO2 XupoXHP78+5an2ZavBvqyo6hQHIDnfwnsHqSZnzM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438543AbfIVS4Q (ORCPT ); Sun, 22 Sep 2019 14:56:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:58142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2438524AbfIVS4N (ORCPT ); Sun, 22 Sep 2019 14:56:13 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D5962186A; Sun, 22 Sep 2019 18:56:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569178572; bh=K0AEGtS3ru3m5o3GBWv+/gtrDrzTVL4cNuryvWAlht0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AmwN/FvrzgPHBqOlpcdsld10hKwS7yU5dZ2+Th+HModSqeuYRD0ofCe93R4/wtR2O H/UWYHtAioZl9JuHX2J+fF9HCNWn2wAbpB163k80z0acNSR7Zsh66qc+qSHMYch+1+ 11WaFqjIjNVmRk2NC7dOrazBp7LNOybLJ945PBzc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Al Stone , "Rafael J . Wysocki" , Sasha Levin , linux-acpi@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 084/128] ACPI / CPPC: do not require the _PSD method Date: Sun, 22 Sep 2019 14:53:34 -0400 Message-Id: <20190922185418.2158-84-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190922185418.2158-1-sashal@kernel.org> References: <20190922185418.2158-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@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 d9ce4b162e2ce..a1aa59849b964 100644 --- a/drivers/acpi/cppc_acpi.c +++ b/drivers/acpi/cppc_acpi.c @@ -369,8 +369,10 @@ 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