Re: [PATCH] Fix lock up when switching off discrete graphics card in Dell XPS 9560 https://bugzilla.kernel.org/show_bug.cgi?id=156341

["Rafael J. Wysocki" <rafael@kernel.org>]

On Tue, Feb 21, 2017 at 8:33 PM, Tobias Schumacher
<tobe.schumacher@gmail.com> wrote:
> Hi Ladislav,
>
> Am Dienstag, den 21.02.2017, 10:41 +0100 schrieb Ladislav Michl:
>> Hi Tobias,
>>
>> On Tue, Feb 21, 2017 at 01:36:25AM +0100, Tobias Schumacher wrote:
>> > Signed-off-by: Tobias Schumacher <tobe.schumacher@gmail.com>
>> > ---
>> >  drivers/acpi/blacklist.c | 14 ++++++++++++++
>> >  1 file changed, 14 insertions(+)
>> >
>> > diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
>> > index 4421f7c..7945f2f 100644
>> > --- a/drivers/acpi/blacklist.c
>> > +++ b/drivers/acpi/blacklist.c
>> > @@ -188,6 +188,20 @@ static struct dmi_system_id
>> > acpi_rev_dmi_table[] __initdata = {
>> >                   DMI_MATCH(DMI_PRODUCT_NAME, "Latitude
>> > 3350"),
>> >             },
>> >     },
>> > +   /*
>> > +    * Resolves issues that cause the system to lock up
>> > +    * under certain conditions when the discrete graphics
>> > +    * card is turned off
>> > +    */
>> > +   {
>> > +    .callback = dmi_enable_rev_override,
>> > +    .ident = "DELL XPS 15 (2017)",
>> > +    .matches = {
>> > +                   DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
>> > +                   DMI_MATCH(DMI_PRODUCT_NAME, "XPS 15
>> > 9560"),
>> > +           },
>> > +   },
>> > +
>> >  #endif
>> >     {}
>> >  };
>>
>> I thought conclusion was _not_ adding any new devices into this
>> evergrowing
>> list. Or am I mistaken? As otherwise I'll sent similar patch for my
>> laptop ;-)
>
> I don't know to be honest - I recently switched back from Mac to Linux
> and searched for a way to get things working properly. Without any
> kernel parameters and patches switching off the discrete graphics will
> lead to lockups when executing for example lspci. Booting with
> 'acpi_osi=! acpi_osi="Windows 2009"' fixes this, but unfortunately the
> touchpad will stop working properly. With this patch both things work.
>
> If the conclusion is not adding new devices here, is there also a
> prefered way of fixing this? I guess getting Dell to fix this would be
> the ideal solution, but what can we do in the meantime? Would adding a
> kernel parameter like acpi_rev that overrides the reported ACPI
> revision be acceptable? The only other solution I could thing of would
> be patching the ACPI tables.

Did you try to boot with acpi_rev_override in the kernel command line?

Thanks,
Rafael