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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 D2E85C433EF for ; Fri, 17 Sep 2021 02:57:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B48CE611C8 for ; Fri, 17 Sep 2021 02:57:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243014AbhIQC6i (ORCPT ); Thu, 16 Sep 2021 22:58:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:43342 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234959AbhIQC6g (ORCPT ); Thu, 16 Sep 2021 22:58:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7693361029; Fri, 17 Sep 2021 02:57:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1631847435; bh=wXfezIYFvZgcQF1nZ2xu2i1izDR8x/hqdRQ/ircZFaY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Myv1BsjhMe1eklE1rtC3/QkxrP6gwsCXkyPdMkm5PUZyd2AgHrEkr6AR/UxAADoKb RVzh9cql/mknQrotoHSXz4yClqOFn7IYA4pGB/fyitZlkx+IH8p8uOy504MiDzconB amRothnKheOt4bSXC9zPS0JM4zE4dg8B07BTjTsB0y3P1jyNsGA+NT2lr3A9a9PpzN QBL96/DKnQQawmvnssOqpLHGk6ZwZ02sHx2bPR1CjckA9vASUBSdbt3KM40knTMdjC kBoxTowvpkc5OpIWpcM6b+odBLWbvnLv0Vr3IdODtekRG5FVyqD2twZVFO6vJIskTd Y0XhlLFpepFZw== Date: Thu, 16 Sep 2021 19:57:13 -0700 From: Jakub Kicinski To: "Paul E. McKenney" Cc: Bjorn Helgaas , x86@kernel.org, jose.souza@intel.com, hpa@zytor.com, bp@alien8.de, mingo@redhat.com, tglx@linutronix.de, kai.heng.feng@canonical.com, bhelgaas@google.com, linux-pci@vger.kernel.org, rudolph@fb.com, xapienz@fb.com, bmilton@fb.com, stable@vger.kernel.org Subject: Re: [PATCH] x86/intel: Disable HPET on another Intel Coffee Lake platform Message-ID: <20210916195713.289a7889@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210916163547.GD4156@paulmck-ThinkPad-P17-Gen-1> References: <20210916131739.1260552-1-kuba@kernel.org> <20210916150707.GA1611532@bjorn-Precision-5520> <20210916083042.5f63163a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210916163547.GD4156@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, 16 Sep 2021 09:35:47 -0700 Paul E. McKenney wrote: > > > How did you pick v5.13? force_disable_hpet() was added by > > > 62187910b0fc ("x86/intel: Add quirk to disable HPET for the Baytrail > > > platform"), which appeared in v3.15. > > > > Erm, good question, it started happening for me (and others with the > > same laptop) with v5.13. I just sort of assumed it was 2e27e793e280 > > ("clocksource: Reduce clocksource-skew threshold"). > > > > It usually takes a day to repro (4 hours was the quickest repro I've > > seen) so bisection was kind of out of question. > > OK, so this is an intermittent condition where HPET is sometimes slow to > access for a short period of time? If that is the case, my thought is > to set the clocksource to be reinitialized (without a splat and without > marking the clocksource unstable), and to splat (and mark the clocksource > unstable) if it is not get a good read after 100 subsequent attempts. > > So as long as the period of slowness lasts for less than 50 seconds, > things would work fine. > > Seem reasonable? Could well be. Initially I thought it was suspend/resume related, then I looked closer and it did happen mostly after resume... but anywhere between 20 minutes to few hours after the resume. I'm here to test less crude patches but since that may take some time I'd hope we can get this merged and into stable ASAP. Hopefully it can make it to 5.13 while that branch is alive and into Fedora. It really makes Coffee Lake machines pretty much unusable.