From patchwork Thu Dec 5 10:05:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leonard Crestez X-Patchwork-Id: 11274601 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DECD8930 for ; Thu, 5 Dec 2019 10:05:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C49672465B for ; Thu, 5 Dec 2019 10:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728794AbfLEKFX (ORCPT ); Thu, 5 Dec 2019 05:05:23 -0500 Received: from inva020.nxp.com ([92.121.34.13]:36560 "EHLO inva020.nxp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726096AbfLEKFX (ORCPT ); Thu, 5 Dec 2019 05:05:23 -0500 Received: from inva020.nxp.com (localhost [127.0.0.1]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id 737121A0B7E; Thu, 5 Dec 2019 11:05:21 +0100 (CET) Received: from inva024.eu-rdc02.nxp.com (inva024.eu-rdc02.nxp.com [134.27.226.22]) by inva020.eu-rdc02.nxp.com (Postfix) with ESMTP id 669EE1A04CC; Thu, 5 Dec 2019 11:05:21 +0100 (CET) Received: from fsr-ub1864-112.ea.freescale.net (fsr-ub1864-112.ea.freescale.net [10.171.82.98]) by inva024.eu-rdc02.nxp.com (Postfix) with ESMTP id 9DC8A2047A; Thu, 5 Dec 2019 11:05:20 +0100 (CET) From: Leonard Crestez To: "Rafael J. Wysocki" , Chanwoo Choi Cc: Matthias Kaehlcke , Kyungmin Park , MyungJoo Ham , =?utf-8?b?QXJ0dXIgxZp3aWdvxYQ=?= , Georgi Djakov , Jacky Bai , Viresh Kumar , NXP Linux Team , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 0/2] PM / devfreq: Add dev_pm_qos support Date: Thu, 5 Dec 2019 12:05:05 +0200 Message-Id: X-Mailer: git-send-email 2.17.1 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Add dev_pm_qos notifiers to devfreq core in order to support frequency limits via dev_pm_qos_add_request. Unlike the rest of devfreq the dev_pm_qos frequency is measured in kHz, this is consistent with current dev_pm_qos usage for cpufreq and allows frequencies above 2Ghz (pm_qos expresses limits as s32). Like with cpufreq the handling of min_freq/max_freq is moved to the dev_pm_qos mechanism. Constraints from userspace are no longer clamped on store, instead all values can be written and we only check against OPPs in a new devfreq_get_freq_range function. This is consistent with the design of dev_pm_qos. Notifiers from pm_qos are executed under a single global dev_pm_qos_mtx and need to take devfreq->lock, this means that calls into dev_pm_qos while holding devfreq->lock are not allowed (lockdep warns about possible deadlocks). Fix this by only adding the qos request and notifiers after devfreq->lock is released inside devfreq_add_device. In theory this means sysfs writes are possible before the min/max requests are initialized so we guard against that explictly. The dev_pm_qos_update_request function would otherwise print a big WARN splat. This series depends on recently accepted series restoring DEV_PM_QOS_MIN/MAX_FREQUENCY inside the pm core: https://patchwork.kernel.org/cover/11262633/ It would be great for this to get into 5.5-rc1 --- Changes since RFC v1: * Trim cover letter * Drop RFC since DEV_PM_QOS_MIN/MAX_FREQUENCY was restored * Collect Acks. * No code changes Link to v1: https://patchwork.kernel.org/cover/11252415/ Changes since "big version" v10: * Drop accepted cleanups * Work with current locking approach (split cleanups into other series) * Drop acks and deliberately relabel as a new series. It still incorporates most previous discussion but takes a different approach to locking. * Don't print errors if devfreq_dev_release is called on error cleanup from devfreq_add_device, just accept that requests and notifiers might not be registered yet. I wish dev_pm_qos cleanups behaved like standard "kfree" and silently did nothing when there's nothing to be done. Link to v10: https://patchwork.kernel.org/project/linux-arm-kernel/list/?series=196443 Leonard Crestez (2): PM / devfreq: Add PM QoS support PM / devfreq: Use PM QoS for sysfs min/max_freq drivers/devfreq/devfreq.c | 151 ++++++++++++++++++++++++++++++++++---- include/linux/devfreq.h | 14 +++- 2 files changed, 145 insertions(+), 20 deletions(-)