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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AF35AC28D13 for ; Thu, 25 Aug 2022 15:48:31 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DEC1210E75B; Thu, 25 Aug 2022 15:48:30 +0000 (UTC) Received: from mail-oa1-x2f.google.com (mail-oa1-x2f.google.com [IPv6:2001:4860:4864:20::2f]) by gabe.freedesktop.org (Postfix) with ESMTPS id F1A8C10E75B; Thu, 25 Aug 2022 15:48:28 +0000 (UTC) Received: by mail-oa1-x2f.google.com with SMTP id 586e51a60fabf-11cb3c811d9so23732116fac.1; Thu, 25 Aug 2022 08:48:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc; bh=rC53qN5yRBX9ZLsKfXDzVV2nrRF5/aNN8DjC44zGscI=; b=A0wiYuHXOtVAdx2cVF9d2wu+8j7RuzDlcZHcvl8ofIHEEXtlf+xc94cvYQ1CVpjuP0 g4MDq5HPhXx/OVskoS7i9u+mBlp7duwdKzulo4EoUjPdVCYfpAwyopCo0RuuIl5M7MLr ijMGzPwPHZ2SFPWMNtSqeAuEJm7QA02g2R4W3AYZhak8c/TG61KVixlQMOeMQ2gy+W8N MV+Mrms8kJPoSIxbLiM0bFjt+AWBf3+7KyzZggiZIqPe39CZZ5VAJWOA2LHTgEhnA3h8 z/Zs0L3ZbVdQhqzMmdWLDtDjPYfUqKgn2n1OUgzfRGhphs2SuXLAnMmbAGECmbI49wIO J2tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc; bh=rC53qN5yRBX9ZLsKfXDzVV2nrRF5/aNN8DjC44zGscI=; b=2gOGDbbCyxBgWqbzIM1GnmGk/FX3bCJMsQACvSY3ng+7NVvdZzNcJrqyYJW8tT0HdT GCD754Xw/LQs7T9LSnSU7M5ySiFK4m0IC5j6rkPc9jk9jNG+mkshz3iGbwrj2hP0qmye 0Z0qgGw2PtDCQzqy4RtaufB5mWgGDWns0ZATOIOlVtHE6cRrDbiuufL6PTjgA7a4iL6Y VyStTPNwFc0gpJGws/7gN/9xSK810Ig9n1OYgzK3mY8ddMmmxEGCFV71GPphAX43cHWi Rj1+tPOi+8j51k+7+skk+Cj10rsZaX+lLPjw0uQ2Z93AlocjDlRrA4rfBIU6sfLTI9fh 1hDw== X-Gm-Message-State: ACgBeo0TZzr3lPnM9Vwr6n1Z5fVR6plshVHRVDMoJ8mvZJ/1SxeuNJaX 02/2Du9prTR1sbqh3zScBFdY1Yz9+eVrRbWrOKc= X-Google-Smtp-Source: AA6agR66nazVE3wlDfBDgpR68PAF2BHkFwZ8PKhcLRIYlt01toN6Li6zbn6KfQDEiOBKqACWN3ASLpAdpnUxxYd6B50= X-Received: by 2002:a05:6870:3484:b0:11e:4465:3d9b with SMTP id n4-20020a056870348400b0011e44653d9bmr674391oah.46.1661442508241; Thu, 25 Aug 2022 08:48:28 -0700 (PDT) MIME-Version: 1.0 References: <1831630.tdWV9SEqCh@kreacher> <8cb42207-b04c-7222-08fa-60c8eb0b3521@amd.com> In-Reply-To: <8cb42207-b04c-7222-08fa-60c8eb0b3521@amd.com> From: Alex Deucher Date: Thu, 25 Aug 2022 11:48:17 -0400 Message-ID: Subject: Re: [PATCH] drm: amd: amdgpu: ACPI: Add comment about ACPI_FADT_LOW_POWER_S0 To: "Limonciello, Mario" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Linux PM , "Pan, Xinhui" , "Rafael J. Wysocki" , LKML , dri-devel@lists.freedesktop.org, Linux ACPI , amd-gfx@lists.freedesktop.org, Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Applied. Thanks! Alex On Thu, Aug 25, 2022 at 3:58 AM Limonciello, Mario wrote: > > On 8/24/2022 12:32, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > According to the ACPI specification [1], the ACPI_FADT_LOW_POWER_S0 > > flag merely means that it is better to use low-power S0 idle on the > > given platform than S3 (provided that the latter is supported) and it > > doesn't preclude using either of them (which of them will be used > > depends on the choices made by user space). > > > > However, on some systems that flag is used to indicate whether or not > > to enable special firmware mechanics allowing the system to save more > > energy when suspended to idle. If that flag is unset, doing so is > > generally risky. > > > > Accordingly, add a comment to explain the ACPI_FADT_LOW_POWER_S0 check > > in amdgpu_acpi_is_s0ix_active(), the purpose of which is otherwise > > somewhat unclear. > > > > Link: https://nam11.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F= %2Fuefi.org%2Fspecs%2FACPI%2F6.4%2F05_ACPI_Software_Programming_Model%2FACP= I_Software_Programming_Model.html%23fixed-acpi-description-table-fadt&d= ata=3D05%7C01%7Cmario.limonciello%40amd.com%7Cf43320dda5114deeb16908da85f69= d3b%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637969591512297179%7CUnkno= wn%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVC= I6Mn0%3D%7C3000%7C%7C%7C&sdata=3Dxp8pNzsXCkLcIJOJFY77yaLkMrvz5he3S%2Bi%= 2FwaxTwwg%3D&reserved=3D0 # [1] > > Signed-off-by: Rafael J. Wysocki > > Reviewed-by: Mario Limonciello > > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > Index: linux-pm/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > --- linux-pm.orig/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > > +++ linux-pm/drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c > > @@ -1066,6 +1066,12 @@ bool amdgpu_acpi_is_s0ix_active(struct a > > (pm_suspend_target_state !=3D PM_SUSPEND_TO_IDLE)) > > return false; > > > > + /* > > + * If ACPI_FADT_LOW_POWER_S0 is not set in the FADT, it is genera= lly > > + * risky to do any special firmware-related preparations for ente= ring > > + * S0ix even though the system is suspending to idle, so return f= alse > > + * in that case. > > + */ > > if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) { > > dev_warn_once(adev->dev, > > "Power consumption will be higher as BIOS h= as not been configured for suspend-to-idle.\n" > > > > > > >