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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17D47C433EF for ; Thu, 10 Feb 2022 10:06:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239294AbiBJKGn (ORCPT ); Thu, 10 Feb 2022 05:06:43 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:52646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236226AbiBJKGn (ORCPT ); Thu, 10 Feb 2022 05:06:43 -0500 Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 904B5C55; Thu, 10 Feb 2022 02:06:44 -0800 (PST) Received: by mail-wr1-x430.google.com with SMTP id h6so8535147wrb.9; Thu, 10 Feb 2022 02:06:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id; bh=FPD4xO1P+78Y/NZipV2Yc+8FswUAtN3q8mItY6ywkSw=; b=QmQF9NFofioCPqaRQ/xtXqTWiKFv4fISuIYU/wppTpOUOYT2oVFrmKM30hyzW9XOXF weBSfLkDIzwC1gq4FYIaxqJgEPcSPslh2ZFFj0QKwr1dZpdkTG4mY26D2d5f11oX5Z8g rdh4qDGsYSsM1lpbHauTAINYBvOoRf9FIJaLrvgFIPLuqVJ2so1FhC+DKdkTa+naJUvg /VVYAeZUAQ89iROPos+uEAXr4t5L3DVAJfZKHVgqtfHnwYAqBayZAnIDILP3VHZwfoRw yNdFl0/SYw3wg5pVhC7EA/ND4xvWLyL2c2zMbD7GLBUCK4Ov6p4pmxrvUsoBRwFtYNxS A3bQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=FPD4xO1P+78Y/NZipV2Yc+8FswUAtN3q8mItY6ywkSw=; b=Q9UO8/jRLHxy81y0SNWx9Q3AnD7cIfxqTSaBduvwfAHNEIVdxV27vNXf0qstzOHBi1 +bwc20LD8bQQNhb4bCh0HI54a0GuUAj8t/neO9k6INJteaPzlwKi3BfbZA2dMXEQgQrA NuKZ+jZS6rj3mKaSXZ8TC9U+VAS4ScwKgzrBNB9uUFu6t9rpGgPwVXEuR/CaH7bD/1u3 L+BxgjAlmpQnBHBpGS2FmNYxZwhZVEj4jv3W4PVx2xoJV5woohHB4m8Dt7FsrmpOtVYr bi+h0/O5ko5sKkw8SoYQLiEUTzIsmFTEEU6qMcu3dKKorskVed8Awg+Fx8kLB6G3GiU4 2g4w== X-Gm-Message-State: AOAM530Eebh13jO2q8T8shUVxzUO+A0aRkHAEvPAJQ4DSvUuR3JSO97v HQyxa9YhKbu374yJnkyzYZA= X-Google-Smtp-Source: ABdhPJz28f2M3YAckbDT3m5BYofZoOYoV0Zalqy9f2eHSZ/BpSZ+pd3QtbiwxftomVxupxK/KE+sow== X-Received: by 2002:adf:f64e:: with SMTP id x14mr5491755wrp.698.1644487602942; Thu, 10 Feb 2022 02:06:42 -0800 (PST) Received: from localhost.localdomain ([87.200.95.144]) by smtp.gmail.com with ESMTPSA id g15sm18817494wri.82.2022.02.10.02.06.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Feb 2022 02:06:42 -0800 (PST) From: Christian Hewitt To: Rob Herring , Mark Rutland , Kevin Hilman , Neil Armstrong , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Christian Hewitt Subject: [PATCH v2 0/2] arm64: dts: meson: remove CPU opps below 1GHz for G12B/SM1 Date: Thu, 10 Feb 2022 10:06:36 +0000 Message-Id: <20220210100638.19130-1-christianshewitt@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Amlogic G12B and SM1 devices experience CPU stalls and random board wedges when the system idles and CPU cores clock down to lower opp points. Recent vendor kernels include a change to remove 100-250MHz (with no explanation) [0] but other downstream sources also remove the 500/667MHz points (also with no explanation). Unless 100-667Mhz opps are removed or the CPU governor forced to performance, stalls are observed, so let's remove them an improve stability/uptime. Numerous people have experienced this issue and I have tested with only the low opp-points removed and numerous voltage tweaks: but it makes no difference. With the opp points present an Odroid N2 or Khadas VIM3 reliably drop off my network after being left idling overnight with UART showing a CPU stall splat. With the opp points removed I see weeks of uninterupted uptime. It's beyond my skills to research what the cause of the stalls might be, but if anyone ever figures it out we can always restore things. NB: This issue is not too widely reported in forums, but that's largely because most of the Amlogic supporting distros have been including this change picked from my kernel patchset for some time. [0] https://github.com/khadas/linux/commit/20e237a4fe9f0302370e24950cb1416e038eee03 Changes since v1: - Split into two patches to allow for separate Fixes tags - Minor edits to commit messages for brevity and typos Christian Hewitt (2): arm64: dts: meson: remove CPU opps below 1GHz for G12B boards arm64: dts: meson: remove CPU opps below 1GHz for SM1 .../boot/dts/amlogic/meson-g12b-a311d.dtsi | 40 ------------------- .../boot/dts/amlogic/meson-g12b-s922x.dtsi | 40 ------------------- arch/arm64/boot/dts/amlogic/meson-sm1.dtsi | 20 ---------- 3 files changed, 100 deletions(-) -- 2.17.1