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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 13CE4CA9EB7 for ; Wed, 23 Oct 2019 09:00:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E900221872 for ; Wed, 23 Oct 2019 09:00:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390630AbfJWJAr (ORCPT ); Wed, 23 Oct 2019 05:00:47 -0400 Received: from mga04.intel.com ([192.55.52.120]:43799 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387829AbfJWJAr (ORCPT ); Wed, 23 Oct 2019 05:00:47 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Oct 2019 02:00:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,220,1569308400"; d="scan'208";a="209878290" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by fmsmga001.fm.intel.com with SMTP; 23 Oct 2019 02:00:43 -0700 Received: by lahna (sSMTP sendmail emulation); Wed, 23 Oct 2019 12:00:42 +0300 Date: Wed, 23 Oct 2019 12:00:42 +0300 From: Mika Westerberg To: Karol Herbst Cc: Bjorn Helgaas , "Rafael J . Wysocki" , LKML , Lyude Paul , Linux PCI , Linux PM , dri-devel , nouveau , Linux ACPI Mailing List Subject: Re: [PATCH v3] pci: prevent putting nvidia GPUs into lower device states on certain intel bridges Message-ID: <20191023090042.GQ2819@lahna.fi.intel.com> References: <20191021133328.GI2819@lahna.fi.intel.com> <20191021140852.GM2819@lahna.fi.intel.com> <20191021154606.GT2819@lahna.fi.intel.com> <20191022124453.GK2819@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 22, 2019 at 02:51:53PM +0200, Karol Herbst wrote: > On Tue, Oct 22, 2019 at 2:45 PM Mika Westerberg > wrote: > > > > On Tue, Oct 22, 2019 at 11:16:14AM +0200, Karol Herbst wrote: > > > I think there is something I totally forgot about: > > > > > > When there was never a driver bound to the GPU, and if runtime power > > > management gets enabled on that device, runtime suspend/resume works > > > as expected (I am not 100% sure on if that always works, but I will > > > recheck that). > > > > AFAIK, if there is no driver bound to the PCI device it is left to D0 > > regardless of the runtime PM state which could explain why it works in > > that case (it is never put into D3hot). > > > > I looked at the acpidump you sent and there is one thing that may > > explain the differences between Windows and Linux. Not sure if you were > > aware of this already, though. The power resource PGOF() method has > > this: > > > > If (((OSYS <= 0x07D9) || ((OSYS == 0x07DF) && (_REV == 0x05)))) { > > ... > > } > > > > I think this is the fallback to some older method of runtime > suspending the device, and I think it will end up touching different > registers on the bridge controller which do not show the broken > behaviour. I think it actually tries to identify older Windows and then Linux (the _REV == 0x05 check comes from that). So at least some point Dell people have experiment this on Linux.