Re: [PATCH v4] drm/i915: Invoke another _DSM to enable MUX on HP Workstation laptops

[Kai-Heng Feng <kai.heng.feng@canonical.com>]

On Fri, Jun 4, 2021 at 11:57 PM Kai-Heng Feng
<kai.heng.feng@canonical.com> wrote:
>
> On Thu, May 20, 2021 at 2:58 PM Kai-Heng Feng
> <kai.heng.feng@canonical.com> wrote:
> >
> > On HP Fury G7 Workstations, graphics output is re-routed from Intel GFX
> > to discrete GFX after S3. This is not desirable, because userspace will
> > treat connected display as a new one, losing display settings.
> >
> > The expected behavior is to let discrete GFX drives all external
> > displays.
> >
> > The platform in question uses ACPI method \_SB.PCI0.HGME to enable MUX.
> > The method is inside the another _DSM, so add the _DSM and call it
> > accordingly.
> >
> > I also tested some MUX-less and iGPU only laptops with that _DSM, no
> > regression was found.
> >
> > v4:
> >  - Rebase.
> >  - Change the DSM name to avoid confusion.
> >  - Move the function call to intel_opregion.
> >
> > v3:
> >  - Remove BXT from names.
> >  - Change the parameter type.
> >  - Fold the function into intel_modeset_init_hw().
> >
> > v2:
> >  - Forward declare struct pci_dev.
> >
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3113
> > References: https://lore.kernel.org/intel-gfx/1460040732-31417-4-git-send-email-animesh.manna@intel.com/
> > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>
> A gentle ping...

Another gentle ping...

>
> > ---
> >  drivers/gpu/drm/i915/display/intel_acpi.c     | 19 +++++++++++++++++++
> >  drivers/gpu/drm/i915/display/intel_acpi.h     |  3 +++
> >  drivers/gpu/drm/i915/display/intel_opregion.c |  3 +++
> >  3 files changed, 25 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c
> > index 833d0c1be4f1..7cfe91fc05f2 100644
> > --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> > @@ -19,6 +19,12 @@ static const guid_t intel_dsm_guid =
> >         GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
> >                   0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
> >
> > +#define INTEL_DSM_FN_GET_BIOS_DATA_FUNCS_SUPPORTED 0 /* No args */
> > +
> > +static const guid_t intel_dsm_guid2 =
> > +       GUID_INIT(0x3e5b41c6, 0xeb1d, 0x4260,
> > +                 0x9d, 0x15, 0xc7, 0x1f, 0xba, 0xda, 0xe4, 0x14);
> > +
> >  static char *intel_dsm_port_name(u8 id)
> >  {
> >         switch (id) {
> > @@ -176,6 +182,19 @@ void intel_unregister_dsm_handler(void)
> >  {
> >  }
> >
> > +void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915)
> > +{
> > +       struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> > +       acpi_handle dhandle;
> > +
> > +       dhandle = ACPI_HANDLE(&pdev->dev);
> > +       if (!dhandle)
> > +               return;
> > +
> > +       acpi_evaluate_dsm(dhandle, &intel_dsm_guid2, INTEL_DSM_REVISION_ID,
> > +                         INTEL_DSM_FN_GET_BIOS_DATA_FUNCS_SUPPORTED, NULL);
> > +}
> > +
> >  /*
> >   * ACPI Specification, Revision 5.0, Appendix B.3.2 _DOD (Enumerate All Devices
> >   * Attached to the Display Adapter).
> > diff --git a/drivers/gpu/drm/i915/display/intel_acpi.h b/drivers/gpu/drm/i915/display/intel_acpi.h
> > index e8b068661d22..9f197401c313 100644
> > --- a/drivers/gpu/drm/i915/display/intel_acpi.h
> > +++ b/drivers/gpu/drm/i915/display/intel_acpi.h
> > @@ -11,11 +11,14 @@ struct drm_i915_private;
> >  #ifdef CONFIG_ACPI
> >  void intel_register_dsm_handler(void);
> >  void intel_unregister_dsm_handler(void);
> > +void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915);
> >  void intel_acpi_device_id_update(struct drm_i915_private *i915);
> >  #else
> >  static inline void intel_register_dsm_handler(void) { return; }
> >  static inline void intel_unregister_dsm_handler(void) { return; }
> >  static inline
> > +void intel_dsm_get_bios_data_funcs_supported(struct drm_i915_private *i915) { return; }
> > +static inline
> >  void intel_acpi_device_id_update(struct drm_i915_private *i915) { return; }
> >  #endif /* CONFIG_ACPI */
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
> > index dfd724e506b5..3855fba70980 100644
> > --- a/drivers/gpu/drm/i915/display/intel_opregion.c
> > +++ b/drivers/gpu/drm/i915/display/intel_opregion.c
> > @@ -1078,6 +1078,9 @@ void intel_opregion_resume(struct drm_i915_private *i915)
> >                 opregion->asle->ardy = ASLE_ARDY_READY;
> >         }
> >
> > +       /* Some platforms abuse the _DSM to enable MUX */
> > +       intel_dsm_get_bios_data_funcs_supported(i915);
> > +
> >         intel_opregion_notify_adapter(i915, PCI_D0);
> >  }
> >
> > --
> > 2.31.1
> >