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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 C67F2C433F5 for ; Tue, 7 Sep 2021 16:02:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A89526112E for ; Tue, 7 Sep 2021 16:02:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234022AbhIGQDT (ORCPT ); Tue, 7 Sep 2021 12:03:19 -0400 Received: from mga11.intel.com ([192.55.52.93]:29275 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230094AbhIGQDS (ORCPT ); Tue, 7 Sep 2021 12:03:18 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10099"; a="217079702" X-IronPort-AV: E=Sophos;i="5.85,274,1624345200"; d="scan'208";a="217079702" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2021 09:01:35 -0700 X-IronPort-AV: E=Sophos;i="5.85,274,1624345200"; d="scan'208";a="546937190" Received: from jbolland-mobl.gar.corp.intel.com ([10.213.119.67]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Sep 2021 09:01:31 -0700 Message-ID: <2a1b000cd101737400f6320ef18c0143d3a5145b.camel@linux.intel.com> Subject: Re: [PATCH v2] cpufreq: intel_pstate: Add Icelake servers support in no-HWP mode From: Srinivas Pandruvada To: Doug Smythies , Giovanni Gherdovich , "Rafael J . Wysocki" Cc: Viresh Kumar , Len Brown , Linux PM list , Linux Kernel Mailing List Date: Tue, 07 Sep 2021 09:01:23 -0700 In-Reply-To: References: <20210513132051.31465-1-ggherdovich@suse.cz> <067ee60e47a0350d01f0c3f216c1032818044b36.camel@suse.cz> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.40.0-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Doug, On Tue, 2021-09-07 at 08:45 -0700, Doug Smythies wrote: > Hi all, > > Recent ASUS BIOS updates have changed the default system > response for this old thread, rendering "intel_pstate=no_hwp" > useless. > > It also raises a question: If BIOS has forced HWP, then how do we > prevent the acpi-cpufreq driver from being used? Read on. Does BIOS has option to enable Intel speed shift with no legacy support? Then this option will not populate ACPI _PSS table. > > On Fri, May 14, 2021 at 3:12 PM Doug Smythies > wrote: > > > > On Fri, May 14, 2021 at 1:33 PM Giovanni Gherdovich < > > ggherdovich@suse.cz> wrote: > > > On Fri, 2021-05-14 at 08:31 -0700, Doug Smythies wrote: > ... > > > > > > when COMETLAKE is not in that list, can you confirm that if you > > > go into the > > > BIOS config at boot, and disable HWP from there, then > > > intel_pstate does *not* load? > > > > Yes, already tested before my original reply. > > > > > Does it say "intel_pstate: CPU model not supported" in the dmesg > > > log? > > > > That I did not check, but if I boot now with an unmodified kernel > > 5.13-rc1 (i.e. without this patch): > > > > [    0.369323] intel_pstate: CPU model not supported > > > > > The control may be somewhere around "power mangement" in the BIOS > > > config, and > > > may be called "Enable/disable Intel Speed Shift". > > > > Yes. > > > > > I'm asking because I've just checked on two Dell laptops, one > > > Skylake and the > > > other Kabylake, and the menu is there in the BIOS config to > > > disable HWP, > > > but if I disable it... nothing happens. "lscpu" shows all the hwp > > > flags as usual: > > > > Motherboard here is ASUS PRIME Z490-A. > > CPU: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz > > > > >     # lscpu | grep Flags | tr ' ' '\n' | grep hwp > > >     hwp > > >     hwp_notify > > >     hwp_act_window > > >     hwp_epp > > > > Here, for some reason I have to do it this way (sudo) or your > > command > > doesn't work properly. Results herein confirmed by looking at the > > "Flags" output manually without filtering: > > > > intel_speed_shift = Disabled in BIOS: > > > > doug@s19:~$ sudo lscpu | tr ' ' '\n' | grep hwp > > doug@s19:~$ > > > > intel_speed_shift = Auto in BIOS > > > > $ sudo lscpu | tr ' ' '\n' | grep hwp > > hwp > > hwp_notify > > hwp_act_window > > hwp_epp > > > > > and turbostat gives me: > > > > > >     # turbostat -Summary -i 1 : 2>&1 | grep MSR_PM_ENABLE > > >     cpu0: MSR_PM_ENABLE: 0x00000001 (HWP) > > > > Here: > > > > intel_speed_shift = Disabled in BIOS: > > > > root@s19:/home/doug# > > /home/doug/temp-k-git/linux/tools/power/x86/turbostat/turbostat > > -Summary -i 1 : 2>&1 | grep MSR_PM_ENABLE > > root@s19:/home/doug# > > > > intel_speed_shift = Auto in BIOS (the default setting) > > > > root@s19:/home/doug# > > /home/doug/temp-k-git/linux/tools/power/x86/turbostat/turbostat > > -Summary -i 1 : 2>&1 | grep MSR_PM_ENABLE > > cpu0: MSR_PM_ENABLE: 0x00000001 (HWP) > > > > or with "intel_pstate=no_hwp" > > > > root@s19:/home/doug# > > /home/doug/temp-k-git/linux/tools/power/x86/turbostat/turbostat > > -Summary -i 1 : 2>&1 | grep MSR_PM_ENABLE > > cpu0: MSR_PM_ENABLE: 0x00000000 (No-HWP) > > > > > Which is to say, on the Intel client machines I have, the > > > firmware doesn't > > > seem to be able to hide HWP from the OS. Buggy BIOS? Maybe, the > > > fact of the > > > matter is, I wouldn't need to add, say, KABYLAKE to that list, > > > based on my > > > experience. > > > > My experience (hardware) differs from yours with respect to this. > > > > > The other side of the issue is that, from my understanding, the > > > preferred/supported way to disable HWP is to boot with > > > intel_pstate=no_hwp, > > Previous correspondence was with BIOS version 1003. There have been 3 > BIOS > releases since then (at least that I know of), 2103, 2201, 2301, and > all of them > have changed the behaviour of the "Auto" setting for Intel Speed > Shift > Technology BIOS setting, forcing it on upon transfer of control to > the OS. > > Where with "intel_pstate=no_hwp" one used to get 0 for MSR_PM_ENABLE > (0x770) they now get 1. So they are forcing Out of band OOB mode. Does bit 8 or 18 in MSR 0x1aa is set? Thanks, Srinivas > > That was for my ASUS Z490-P Motherboard. > For my ASUS Z390-A Motherboard (actually a windows 10 computer now), > with an older BIOS, things still work properly for > "intel_pstate=no_hwp", and > while there is a newer BIOS, I will not install it as it is also not > possible to > rollback. > > I have had an escalation in progress with ASUS about this for about a > month, > and while they have been responsive we have communications/language > issues and have yet to even agree that there is an issue. > > I have been working with this incomplete patch: > > diff --git a/drivers/cpufreq/intel_pstate.c > b/drivers/cpufreq/intel_pstate.c > index bb4549959b11..7dcc51ee56ea 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -3347,17 +3347,27 @@ device_initcall(intel_pstate_init); > >  static int __init intel_pstate_setup(char *str) >  { > +       /* The following needs to be conditional on CPUID with EAX 6 > */ > +       /* CPUID.06H:EAX[bit 7], which I do not know how to do. */ > +       /* Avoid doing checking and printing multiple times, */ > +       /* which I do not know why it does. */ > +       if(!force_load){ > +               if(intel_pstate_hwp_is_enabled()){ > +                       pr_info("HWP enabled by BIOS\n"); > +                       force_load = 1; > +               } > +       } >         if (!str) >                 return -EINVAL; > > -       if (!strcmp(str, "disable")) > +       if (!strcmp(str, "disable") && !force_load) >                 no_load = 1; > -       else if (!strcmp(str, "active")) > +       if (!strcmp(str, "active") && !no_load) >                 default_driver = &intel_pstate; >         else if (!strcmp(str, "passive")) >                 default_driver = &intel_cpufreq; > > -       if (!strcmp(str, "no_hwp")) { > +       if (!strcmp(str, "no_hwp") && !force_load) { >                 pr_info("HWP disabled\n"); >                 no_hwp = 1; >         } > > Which has troubles when HWP has been disabled by BIOS, but otherwise > works well. > > HWP Disabled by BIOS: > > doug@s19:~$ sudo dmesg | grep intel_pstate > [sudo] password for doug: > [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=314 intel_pstate=active intel_pstate=no_hwp > msr.allow_writes=on cpuidle.governor=teo > [    0.000000]  intel_pstate_setup+0x24/0x151 > [    0.000000]  intel_pstate_setup+0x24/0x151 > [    0.000000] intel_pstate: HWP disabled > [    0.051278] Kernel command line: > BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=314 intel_pstate=active intel_pstate=no_hwp > msr.allow_writes=on cpuidle.governor=teo > [    0.393236] intel_pstate: Intel P-state driver initializing > > HWP force enabled by BIOS, which is the only other option with the > newer BIOS: > > doug@s19:~$ sudo dmesg | grep intel_pstate > [sudo] password for doug: > [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=314 intel_pstate=active intel_pstate=no_hwp > msr.allow_writes=on cpuidle.governor=teo > [    0.000000] intel_pstate: HWP enabled by BIOS > [    0.049205] Kernel command line: > BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=314 intel_pstate=active intel_pstate=no_hwp > msr.allow_writes=on cpuidle.governor=teo > [    0.370662] intel_pstate: Intel P-state driver initializing > [    0.371590] intel_pstate: HWP enabled > > HWP forced by BIOS, disable intel_pstate: > > doug@s19:~$ sudo dmesg | grep intel_pstate > [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=300 intel_pstate=disable msr.allow_writes=on > cpuidle.governor=teo > [    0.000000] intel_pstate: HWP enabled by BIOS > [    0.049133] Kernel command line: > BOOT_IMAGE=/boot/vmlinuz-5.14.0-ipstate4 > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=300 intel_pstate=disable msr.allow_writes=on > cpuidle.governor=teo > [    0.370519] intel_pstate: Intel P-state driver initializing > [    0.371451] intel_pstate: HWP enabled > doug@s19:~$ cat /sys/devices/system/cpu/cpu5/cpufreq/scaling_driver > intel_pstate > > HWP forced by BIOS, disable intel_pstate:, unpatched kernel 5.14: > > doug@s19:~$ sudo dmesg | grep intel_pstate > [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.14.0-stock > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=300 intel_pstate=disable msr.allow_writes=on > cpuidle.governor=teo > [    0.049108] Kernel command line: > BOOT_IMAGE=/boot/vmlinuz-5.14.0-stock > root=UUID=0ac356c1-caa9-4c2e-8229-4408bd998dbd ro ipv6.disable=1 > consoleblank=300 intel_pstate=disable msr.allow_writes=on > cpuidle.governor=teo > doug@s19:~$ cat /sys/devices/system/cpu/cpu5/cpufreq/scaling_driver > acpi-cpufreq > doug@s19:~$ sudo rdmsr 0x770 > 1 > > Observe the driver ended up as acpi-cpufreq, but with HWP enabled. > > ... Doug