From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lekensteyn.nl ([178.21.112.251]:44737 "EHLO lekensteyn.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751593AbcH3TVi (ORCPT ); Tue, 30 Aug 2016 15:21:38 -0400 Date: Tue, 30 Aug 2016 21:21:12 +0200 From: Peter Wu To: Ilia Mirkin Cc: Roland Singer , Emil Velikov , Bjorn Helgaas , Linux PCI , "Linux-Kernel@Vger. Kernel. Org" , ML dri-devel , "linux-acpi@vger.kernel.org" Subject: Re: Kernel Freeze with American Megatrends BIOS Message-ID: <20160830192112.GA18045@al> References: <20160829235403.GA14177@localhost> <1d1bfdc2-f23d-9816-e4e3-ae676105dc39@desertbit.com> <20160830130634.GA16426@localhost> <735da66c-aaf3-8c27-2d59-f62e8c85d3aa@desertbit.com> <43ce7a5b-8331-fec2-f598-afcb13ba3785@desertbit.com> <1c761bab-f82b-3f43-c4f0-c7a8eff94f25@desertbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-pci-owner@vger.kernel.org List-ID: On Tue, Aug 30, 2016 at 02:13:46PM -0400, Ilia Mirkin wrote: > On Tue, Aug 30, 2016 at 2:02 PM, Roland Singer > wrote: > > I configured bbswitch to not set any states automatically... > > So it's possible to obtain and verify the GPU power state. > > > > However I removed the bbswitch module and booted with nouveau. > > > > Kernel 4.7.2: nouveau switches the discrete GPU off. > > I can't trigger the freeze, because bbswitch is missing. > > I'll work with the system and see if it will freeze. > > > > Kernel 4.8-rc4: nouveau does not care about the power state and > > the discrete GPU is never switched off. I will notice > > this, because the second cooling FAN will stop... > > Same log messages as send before. > > That's surprising. I believe there's an issue with the new logic when > there's an HDMI audio subdevice. However that only appears if there's > a cable plugged in, at least in the systems Peter tested. You should > be able to see whether it's there or not with 'lspci'. I doubt that the audio device is responsible here, that should only show up after following very specific steps (runtime suspend/resume (PCI or ACPI magic), remove PCI device, rescan bus). > You can check for sure by looking in the vgaswitcheroo state. It > should say DynOff when it's powered off. > > Either way, I think using bbswitch + nouveau isn't supported by > anyone, so if you want to use it that way, you're on your own. (You > may want to load nouveau with runpm=0 so that nouveau doesn't try to > manage the GPU suspend stuff.) I understood that Roland's intent is to check the power state, not use the suspend functionality of bbswitch, if you load bbswitch without module options amd do not write to /proc/bbswitch, then it allows you to read out the actual status (you could also just use lspci -H1 for that though). -- Kind regards, Peter Wu https://lekensteyn.nl