linux-kernel - Re: Kernel Freeze with American Megatrends BIOS

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Date:   Tue, 30 Aug 2016 11:48:14 -0400
From:   Ilia Mirkin <imirkin@...m.mit.edu>
To:     Roland Singer <roland.singer@...ertbit.com>
Cc:     Emil Velikov <emil.l.velikov@...il.com>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Linux PCI <linux-pci@...r.kernel.org>,
        "Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>
Subject: Re: Kernel Freeze with American Megatrends BIOS

On Tue, Aug 30, 2016 at 11:44 AM, Ilia Mirkin <imirkin@...m.mit.edu> wrote:
> On Tue, Aug 30, 2016 at 11:25 AM, Roland Singer
> <roland.singer@...ertbit.com> wrote:
>> I tried these scenarios:
>>
>> 1. Booted the system without the bbswitch module. The nouveau module
>>    was loaded and is responsible for the power management of the GPU.
>>    The graphical session freezes after some minutes...
>>
>> 2. Booted the system without bbswitch and with nouveau blacklisted.
>>    Manually loaded bbswitch to switch off the discrete GPU.
>>    Same freeze after a while or by explicitly obtaining the GPU state.
>>
>> Is there a possibility to switch off the discrete card without bbswitch?
>> If this is possible, then I could test this without nouveau and bbswitch
>> at all. If the system hangs, then it is not the video driver nor bbswitch.
>
> You can use acpi_call (a random search points to
> https://github.com/mkottman/acpi_call, but I don't know if that's the
> "official" version) - need to find the right method to call, but
> that's basically all it takes to acpi-suspend a gpu.
>
> Separately, there was a recent fix to ... something, including but not
> limited to nouveau, involving hangs on gpu suspend on newer laptops. I
> don't think it's upstream yet. Look for patches from Lukas Wunner.

Er oops. Looks like I misremembered. Patches are from Peter Wu, and at
least one of them is in v4.8-rc1:

commit 692a17dcc2922a91c6bcf11b3321503a3377b1b1
Author: Peter Wu <peter@...ensteyn.nl>
Date:   Fri Jul 15 15:12:18 2016 +0200

    drm/nouveau/acpi: fix lockup with PCIe runtime PM

along with a number of other related patches. It's not clear which
kernel you were trying this with... can you give v4.8-rcN a shot?

  -ilia