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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 22C74C433E0 for ; Mon, 4 Jan 2021 23:20:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E08442253D for ; Mon, 4 Jan 2021 23:20:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbhADXUw convert rfc822-to-8bit (ORCPT ); Mon, 4 Jan 2021 18:20:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:55182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726026AbhADXUw (ORCPT ); Mon, 4 Jan 2021 18:20:52 -0500 Received: by mail.kernel.org (Postfix) with ESMTPS id B07F52253D for ; Mon, 4 Jan 2021 23:20:11 +0000 (UTC) From: bugzilla-daemon@bugzilla.kernel.org To: linux-pm@vger.kernel.org Subject: [Bug 210993] Intel frequency scaling causes electrical noise on 10th gen CPUs Date: Mon, 04 Jan 2021 23:20:11 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Power Management X-Bugzilla-Component: cpufreq X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: currojerez@riseup.net X-Bugzilla-Status: NEEDINFO X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: linux-pm@vger.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=210993 --- Comment #7 from Francisco Jerez (currojerez@riseup.net) --- (In reply to Karol Herbst from comment #6) > > > Does disabling some specific idle state (e.g via > > /sys/devices/system/cpu/cpu*/cpuidle/state*/disable) have any effect on the > > noise? > > disabling all except state0 stops the noise. Ah that makes sense, that sounds like the culprit might be a noisy power supply coupled to the oscillation of the processor's current draw caused by repeated C-state transitions. If that's the case you may be able to tweak the latency parameters to make sure the oscillation frequency is outside the audible range, though I'm not sure if it would make sense to upstream such a change since it will likely come at an energy cost (Though I would expect the cost to be minor as long as the processor can still reach the deepest sleep state in the steady state while idle, might be a good trade-off in your specific case if this is particularly annoying to you). -- You may reply to this email to add a comment. You are receiving this mail because: You are the assignee for the bug.