Nouveau - Jul 2020 - [PATCH] RFC: ACPI / OSI: remove workarounds for hybrid graphics laptops

On Fri, Jul 17, 2020 at 9:52 PM Alex Hung <alex.hung at canonical.com>
wrote:
>
> On 2020-07-17 1:05 p.m., Karol Herbst wrote:
> > It's hard to figure out what systems are actually affected and
right now I
> > don't see a good way of removing those...
> >
> > But I'd like to see thos getting removed and drivers fixed instead
(which
> > happened at least for nouveau).
> >
> > And as mentioned before, I prefer people working on fixing issues
instead
> > of spending time to add firmware level workarounds which are hard to
know
> > to which systems they apply to, hard to remove and basically a big
huge
> > pain to work with.> In the end I have no idea how to even figure
out what systems are affected
> > and which not by this, so I have no idea how to even verify we can
safely
> > remove this (which just means those are impossible to remove unless we
risk
> > breaking systems, which again makes those supper annoying to deal
with).
> >
> > Also from the comments it's hard to get what those bits really do.
Are they
> > just preventing runtime pm or do the devices are powered down when
booting?
> > I am sure it's the former, still...
> >
> > Please, don't do this again.
> >
> > For now, those workaround prevent power savings on systems those
workaround
> > applies to, which might be any so those should get removed asap and if
> > new issues arrise removing those please do a proper bug report and we
can
> > look into it and come up with a proper fix (and keep this patch out
until
> > we resolve all of those).
> >
> > Signed-off-by: Karol Herbst <kherbst at redhat.com>
> > CC: Alex Hung <alex.hung at canonical.com>
> > CC: "Rafael J. Wysocki" <rjw at rjwysocki.net>
> > CC: Len Brown <lenb at kernel.org>
> > CC: Lyude Paul <lyude at redhat.com>
> > CC: linux-kernel at vger.kernel.org
> > CC: dri-devel at lists.freedesktop.org
> > CC: nouveau at lists.freedesktop.org
> > ---
> >  drivers/acpi/osi.c | 24 ------------------------
> >  1 file changed, 24 deletions(-)
> >
> > diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c
> > index 9f68538091384..d4405e1ca9b97 100644
> > --- a/drivers/acpi/osi.c
> > +++ b/drivers/acpi/osi.c
> > @@ -44,30 +44,6 @@ osi_setup_entries[OSI_STRING_ENTRIES_MAX]
__initdata = {
> >       {"Processor Device", true},
> >       {"3.0 _SCP Extensions", true},
> >       {"Processor Aggregator Device", true},
> > -     /*
> > -      * Linux-Dell-Video is used by BIOS to disable RTD3 for NVidia
graphics
> > -      * cards as RTD3 is not supported by drivers now.  Systems with
NVidia
> > -      * cards will hang without RTD3 disabled.
> > -      *
> > -      * Once NVidia drivers officially support RTD3, this _OSI
strings can
> > -      * be removed if both new and old graphics cards are supported.
> > -      */
> > -     {"Linux-Dell-Video", true},
> > -     /*
> > -      * Linux-Lenovo-NV-HDMI-Audio is used by BIOS to power on
NVidia's HDMI
> > -      * audio device which is turned off for power-saving in Windows
OS.
> > -      * This power management feature observed on some Lenovo
Thinkpad
> > -      * systems which will not be able to output audio via HDMI
without
> > -      * a BIOS workaround.
> > -      */
> > -     {"Linux-Lenovo-NV-HDMI-Audio", true},
> > -     /*
> > -      * Linux-HPI-Hybrid-Graphics is used by BIOS to enable dGPU to
> > -      * output video directly to external monitors on HP Inc. mobile
> > -      * workstations as Nvidia and AMD VGA drivers provide limited
> > -      * hybrid graphics supports.
> > -      */
> > -     {"Linux-HPI-Hybrid-Graphics", true},
> >  };
> >
> >  static u32 acpi_osi_handler(acpi_string interface, u32 supported)
> >
>
> The changes were discussed and tested a while ago, and no crashes were
> observed. Thanks for solving PM issues in nouveau.
>
> Acked-by: Alex Hung <alex.hung at canonical.com>
>
By any chance, do you have a list of systems implementing those workarounds?

On 2020-07-19 1:50 p.m., Karol Herbst wrote:
> On Fri, Jul 17, 2020 at 9:52 PM Alex Hung <alex.hung at
canonical.com> wrote:
>>
>> On 2020-07-17 1:05 p.m., Karol Herbst wrote:
>>> It's hard to figure out what systems are actually affected and
right now I
>>> don't see a good way of removing those...
>>>
>>> But I'd like to see thos getting removed and drivers fixed
instead (which
>>> happened at least for nouveau).
>>>
>>> And as mentioned before, I prefer people working on fixing issues
instead
>>> of spending time to add firmware level workarounds which are hard
to know
>>> to which systems they apply to, hard to remove and basically a big
huge
>>> pain to work with.> In the end I have no idea how to even figure
out what systems are affected
>>> and which not by this, so I have no idea how to even verify we can
safely
>>> remove this (which just means those are impossible to remove unless
we risk
>>> breaking systems, which again makes those supper annoying to deal
with).
>>>
>>> Also from the comments it's hard to get what those bits really
do. Are they
>>> just preventing runtime pm or do the devices are powered down when
booting?
>>> I am sure it's the former, still...
>>>
>>> Please, don't do this again.
>>>
>>> For now, those workaround prevent power savings on systems those
workaround
>>> applies to, which might be any so those should get removed asap and
if
>>> new issues arrise removing those please do a proper bug report and
we can
>>> look into it and come up with a proper fix (and keep this patch out
until
>>> we resolve all of those).
>>>
>>> Signed-off-by: Karol Herbst <kherbst at redhat.com>
>>> CC: Alex Hung <alex.hung at canonical.com>
>>> CC: "Rafael J. Wysocki" <rjw at rjwysocki.net>
>>> CC: Len Brown <lenb at kernel.org>
>>> CC: Lyude Paul <lyude at redhat.com>
>>> CC: linux-kernel at vger.kernel.org
>>> CC: dri-devel at lists.freedesktop.org
>>> CC: nouveau at lists.freedesktop.org
>>> ---
>>>  drivers/acpi/osi.c | 24 ------------------------
>>>  1 file changed, 24 deletions(-)
>>>
>>> diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c
>>> index 9f68538091384..d4405e1ca9b97 100644
>>> --- a/drivers/acpi/osi.c
>>> +++ b/drivers/acpi/osi.c
>>> @@ -44,30 +44,6 @@ osi_setup_entries[OSI_STRING_ENTRIES_MAX]
__initdata = {
>>>       {"Processor Device", true},
>>>       {"3.0 _SCP Extensions", true},
>>>       {"Processor Aggregator Device", true},
>>> -     /*
>>> -      * Linux-Dell-Video is used by BIOS to disable RTD3 for
NVidia graphics
>>> -      * cards as RTD3 is not supported by drivers now.  Systems
with NVidia
>>> -      * cards will hang without RTD3 disabled.
>>> -      *
>>> -      * Once NVidia drivers officially support RTD3, this _OSI
strings can
>>> -      * be removed if both new and old graphics cards are
supported.
>>> -      */
>>> -     {"Linux-Dell-Video", true},
>>> -     /*
>>> -      * Linux-Lenovo-NV-HDMI-Audio is used by BIOS to power on
NVidia's HDMI
>>> -      * audio device which is turned off for power-saving in
Windows OS.
>>> -      * This power management feature observed on some Lenovo
Thinkpad
>>> -      * systems which will not be able to output audio via HDMI
without
>>> -      * a BIOS workaround.
>>> -      */
>>> -     {"Linux-Lenovo-NV-HDMI-Audio", true},
>>> -     /*
>>> -      * Linux-HPI-Hybrid-Graphics is used by BIOS to enable dGPU
to
>>> -      * output video directly to external monitors on HP Inc.
mobile
>>> -      * workstations as Nvidia and AMD VGA drivers provide limited
>>> -      * hybrid graphics supports.
>>> -      */
>>> -     {"Linux-HPI-Hybrid-Graphics", true},
>>>  };
>>>
>>>  static u32 acpi_osi_handler(acpi_string interface, u32 supported)
>>>
>>
>> The changes were discussed and tested a while ago, and no crashes were
>> observed. Thanks for solving PM issues in nouveau.
>>
>> Acked-by: Alex Hung <alex.hung at canonical.com>
>>
> 
> By any chance, do you have a list of systems implementing those
workarounds?
> 
I don't keep a list but the workaround, in theory, should only apply to
the systems with the specific nvidia hardware.

I reminded OEMs and ODMs that these _OSI strings were temporary
solutions, and highlighted we were going to remove them after our
discussion last year. If they were paying attentions recent systems
shouldn't have these _OSI strings.

-- 
Cheers,
Alex Hung

On Mon, Jul 20, 2020 at 3:19 AM Alex Hung <alex.hung at canonical.com>
wrote:
>
> On 2020-07-19 1:50 p.m., Karol Herbst wrote:
> > On Fri, Jul 17, 2020 at 9:52 PM Alex Hung <alex.hung at
canonical.com> wrote:
> >>
> >> On 2020-07-17 1:05 p.m., Karol Herbst wrote:
> >>> It's hard to figure out what systems are actually affected
and right now I
> >>> don't see a good way of removing those...
> >>>
> >>> But I'd like to see thos getting removed and drivers fixed
instead (which
> >>> happened at least for nouveau).
> >>>
> >>> And as mentioned before, I prefer people working on fixing
issues instead
> >>> of spending time to add firmware level workarounds which are
hard to know
> >>> to which systems they apply to, hard to remove and basically a
big huge
> >>> pain to work with.> In the end I have no idea how to even
figure out what systems are affected
> >>> and which not by this, so I have no idea how to even verify we
can safely
> >>> remove this (which just means those are impossible to remove
unless we risk
> >>> breaking systems, which again makes those supper annoying to
deal with).
> >>>
> >>> Also from the comments it's hard to get what those bits
really do. Are they
> >>> just preventing runtime pm or do the devices are powered down
when booting?
> >>> I am sure it's the former, still...
> >>>
> >>> Please, don't do this again.
> >>>
> >>> For now, those workaround prevent power savings on systems
those workaround
> >>> applies to, which might be any so those should get removed
asap and if
> >>> new issues arrise removing those please do a proper bug report
and we can
> >>> look into it and come up with a proper fix (and keep this
patch out until
> >>> we resolve all of those).
> >>>
> >>> Signed-off-by: Karol Herbst <kherbst at redhat.com>
> >>> CC: Alex Hung <alex.hung at canonical.com>
> >>> CC: "Rafael J. Wysocki" <rjw at rjwysocki.net>
> >>> CC: Len Brown <lenb at kernel.org>
> >>> CC: Lyude Paul <lyude at redhat.com>
> >>> CC: linux-kernel at vger.kernel.org
> >>> CC: dri-devel at lists.freedesktop.org
> >>> CC: nouveau at lists.freedesktop.org
> >>> ---
> >>>  drivers/acpi/osi.c | 24 ------------------------
> >>>  1 file changed, 24 deletions(-)
> >>>
> >>> diff --git a/drivers/acpi/osi.c b/drivers/acpi/osi.c
> >>> index 9f68538091384..d4405e1ca9b97 100644
> >>> --- a/drivers/acpi/osi.c
> >>> +++ b/drivers/acpi/osi.c
> >>> @@ -44,30 +44,6 @@ osi_setup_entries[OSI_STRING_ENTRIES_MAX]
__initdata = {
> >>>       {"Processor Device", true},
> >>>       {"3.0 _SCP Extensions", true},
> >>>       {"Processor Aggregator Device", true},
> >>> -     /*
> >>> -      * Linux-Dell-Video is used by BIOS to disable RTD3 for
NVidia graphics
> >>> -      * cards as RTD3 is not supported by drivers now. 
Systems with NVidia
> >>> -      * cards will hang without RTD3 disabled.
> >>> -      *
> >>> -      * Once NVidia drivers officially support RTD3, this
_OSI strings can
> >>> -      * be removed if both new and old graphics cards are
supported.
> >>> -      */
> >>> -     {"Linux-Dell-Video", true},
> >>> -     /*
> >>> -      * Linux-Lenovo-NV-HDMI-Audio is used by BIOS to power
on NVidia's HDMI
> >>> -      * audio device which is turned off for power-saving in
Windows OS.
> >>> -      * This power management feature observed on some Lenovo
Thinkpad
> >>> -      * systems which will not be able to output audio via
HDMI without
> >>> -      * a BIOS workaround.
> >>> -      */
> >>> -     {"Linux-Lenovo-NV-HDMI-Audio", true},
> >>> -     /*
> >>> -      * Linux-HPI-Hybrid-Graphics is used by BIOS to enable
dGPU to
> >>> -      * output video directly to external monitors on HP Inc.
mobile
> >>> -      * workstations as Nvidia and AMD VGA drivers provide
limited
> >>> -      * hybrid graphics supports.
> >>> -      */
> >>> -     {"Linux-HPI-Hybrid-Graphics", true},
> >>>  };
> >>>
> >>>  static u32 acpi_osi_handler(acpi_string interface, u32
supported)
> >>>
> >>
> >> The changes were discussed and tested a while ago, and no crashes
were
> >> observed. Thanks for solving PM issues in nouveau.
> >>
> >> Acked-by: Alex Hung <alex.hung at canonical.com>
> >>
> >
> > By any chance, do you have a list of systems implementing those
workarounds?
> >
>
> I don't keep a list but the workaround, in theory, should only apply to
> the systems with the specific nvidia hardware.
>
> I reminded OEMs and ODMs that these _OSI strings were temporary
> solutions, and highlighted we were going to remove them after our
> discussion last year. If they were paying attentions recent systems
> shouldn't have these _OSI strings.
>
Right.. but I am actually wondering because I never saw those strings
in the wild or not on the Dell and Lenovo systems I was testing on. So
I think we might want to ask the vendors themselves and verify on
those systems.
> --
> Cheers,
> Alex Hung
>