From patchwork Tue Jul 17 16:13:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10530091 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8706760247 for ; Tue, 17 Jul 2018 16:15:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6A7A529578 for ; Tue, 17 Jul 2018 16:15:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5AC91295BF; Tue, 17 Jul 2018 16:15:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 678DE29578 for ; Tue, 17 Jul 2018 16:15:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729683AbeGQQsX (ORCPT ); Tue, 17 Jul 2018 12:48:23 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:42458 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729671AbeGQQsX (ORCPT ); Tue, 17 Jul 2018 12:48:23 -0400 Received: from 79.184.255.17.ipv4.supernova.orange.pl (79.184.255.17) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83) id c70ab66d59d54dc9; Tue, 17 Jul 2018 18:14:57 +0200 From: "Rafael J. Wysocki" To: Andreas Herrmann , Srinivas Pandruvada Cc: "Rafael J. Wysocki" , Peter Zijlstra , Frederic Weisbecker , Viresh Kumar , Linux PM , Linux Kernel Mailing List Subject: [PATCH] cpufreq: intel_pstate: Load when ACPI PCCH is present Date: Tue, 17 Jul 2018 18:13:19 +0200 Message-ID: <8115130.Fhkpr82c7G@aspire.rjw.lan> In-Reply-To: <20180717140336.ayovaz4ksdlak6bb@suselix> References: <20180717065048.74mmgk4t5utjaa6a@suselix> <20180717102136.snayvzmv2h3dcwiq@suselix> <20180717140336.ayovaz4ksdlak6bb@suselix> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Currently, intel_pstate doesn't load if _PSS is not present on HP Proliant systems, because it expects the firmware to take over CPU performance scaling in that case. However, if ACPI PCCH is present, the firmware expects the kernel to use it for CPU performance scaling and the pcc-cpufreq driver is loaded for that. Unfortunately, the firmware interface used by that driver is not scalable for fundamental reasons, so pcc-cpufreq is way suboptimal on systems with more than just a few CPUs. In fact, it is better to avoid using it at all. For this reason, modify intel_pstate to look for ACPI PCCH if _PSS is not present and load if it is there. Fixes: fbbcdc0744da (intel_pstate: skip the driver if ACPI has power mgmt option) Reported-by: Andreas Herrmann Tested-by: Andreas Herrmann Reviewed-by: Andreas Herrmann Cc: 4.17+ # 4.17+ Signed-off-by: Rafael J. Wysocki Acked-by: Srinivas Pandruvada --- drivers/cpufreq/intel_pstate.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -2391,6 +2391,18 @@ static bool __init intel_pstate_no_acpi_ return true; } +static bool __init intel_pstate_no_acpi_pcch(void) +{ + acpi_status status; + acpi_handle handle; + + status = acpi_get_handle(NULL, "\\_SB", &handle); + if (ACPI_FAILURE(status)) + return true; + + return !acpi_has_method(handle, "PCCH"); +} + static bool __init intel_pstate_has_acpi_ppc(void) { int i; @@ -2450,7 +2462,10 @@ static bool __init intel_pstate_platform switch (plat_info[idx].data) { case PSS: - return intel_pstate_no_acpi_pss(); + if (!intel_pstate_no_acpi_pss()) + return false; + + return intel_pstate_no_acpi_pcch(); case PPC: return intel_pstate_has_acpi_ppc() && !force_load; }