From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755742AbcH2THo (ORCPT ); Mon, 29 Aug 2016 15:07:44 -0400 Received: from mail.kernel.org ([198.145.29.136]:46262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751271AbcH2THm (ORCPT ); Mon, 29 Aug 2016 15:07:42 -0400 Date: Mon, 29 Aug 2016 14:07:37 -0500 From: Bjorn Helgaas To: Roland Singer Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: Kernel Freeze with American Megatrends BIOS Message-ID: <20160829190737.GA4053@localhost> References: <004c7dbe-2014-c691-29d1-7a45f3b73dfa@desertbit.com> <20160829160210.GA24451@localhost> <1cca943f-eab4-4054-4a13-31370d7ae057@desertbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1cca943f-eab4-4054-4a13-31370d7ae057@desertbit.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 29, 2016 at 08:46:17PM +0200, Roland Singer wrote: > Hi Bjorn, > > I am using the bbswitch kernel module to switch off/on the GPU and > to obtain the GPU power state. > Obtaining the GPU state immediately after starting the graphical user > session freezes the system. > > This code triggers something, which is responsible for the freeze. > > --- > // Returns 1 if the card is disabled, 0 if enabled > static int is_card_disabled(void) { > u32 cfg_word; > // read first config word which contains Vendor and Device ID. If all bits > // are enabled, the device is assumed to be off > pci_read_config_dword(dis_dev, 0, &cfg_word); > // if one of the bits is not enabled (the card is enabled), the inverted > // result will be non-zero and hence logical not will make it 0 ("false") > return !~cfg_word; > } > > static int bbswitch_proc_show(struct seq_file *seqfp, void *p) { > // show the card state. Example output: 0000:01:00:00 ON > dis_dev_get(); > seq_printf(seqfp, "%s %s\n", dev_name(&dis_dev->dev), > is_card_disabled() ? "OFF" : "ON"); > dis_dev_put(); > return 0; > } > --- > > Either dis_dev_get or pci_read_config_dword is the trigger. What happens if you remove the call to is_card_disabled()? Does the system still freeze if you only do the dis_dev_get()/dis_dev_put()? > Link to the bbswitch module source code: > https://github.com/Bumblebee-Project/bbswitch/blob/master/bbswitch.c#L333 > > > Am 29.08.2016 um 18:02 schrieb Bjorn Helgaas: > > [+cc linux-acpi, linux-kernel, dri-devel] > > > > Hi Roland, > > > > I have no idea how to debug this problem. Are you seeing something > > that suggests it may be a PCI problem? > > > > On Tue, Aug 23, 2016 at 11:23:45AM +0200, Roland Singer wrote: > >> Hi, > >> > >> hope somebody can help me fix this kernel problem which affects the following machines: > >> > >> - Clevo P651RA (i7-6700HQ/GTX 965M, part of the P6xxRx family which are also affected) > >> - MSI GE62 Apache Pro (i7-6700HQ/GTX 960M) > >> - Gigabyte P35V5 (i7-6700HQ/GTX 970M) > >> - Razer Blade 14" (2016) (i7-6700HQ/GTX 970M) (BIOS 5.11, 04/07/2016) > >> > >> > >> The kernel freezes if the graphical user session (Xorg & Wayland) is > >> started with a switched off discrete GPU card (NVIDIA). > >> If the discrete GPU is switched off after the graphical session start, > >> then everything works as expected, until the graphical session is restarted. > >> > >> This problem seams to be linked to specific BIOS settings. If the computer > >> is started with the following command line: > >> > >> acpi_osi=! acpi_osi="Windows 2009" > >> > >> then the kernel freeze does not occur anymore. However this required a special > >> ACPI DSDT firmware patch for the Razer Blade 2016 laptop: > >> > >> https://github.com/m4ng0squ4sh/razer_blade_14_2016_acpi_dsdt > >> > >> I strongly recommend to fix this in the kernel and I am ready to help and solve > >> this problem with some help. > >> > >> Here is a link to the GitHub issue with further information: > >> > >> https://github.com/Bumblebee-Project/Bumblebee/issues/764#issuecomment-241212595 > >> > >> Here are some more detailed information: > >> > >> https://github.com/Lekensteyn/acpi-stuff/blob/master/Clevo-P651RA/notes.txt > >> > >> Hope somebody can help. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html