On Fri, 2022-06-03 at 13:14 +0000, Hogander, Jouni wrote:
> On Fri, 2022-06-03 at 15:43 +0300, Jani Nikula wrote:
> > On Fri, 03 Jun 2022, Jouni Högander <jouni.hogander@xxxxxxxxx> wrote:
> > > Export headless sku bit (bit 13) from opregion->header->pcon as an
> > > interface to check if our device is headless configuration.
> > >
> > > Bspec: 53441
> > > Signed-off-by: Jouni Högander <jouni.hogander@xxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/i915/display/intel_opregion.c | 12 ++++++++++++
> > > drivers/gpu/drm/i915/display/intel_opregion.h | 7 +++++++
> > > 2 files changed, 19 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c
> > > b/drivers/gpu/drm/i915/display/intel_opregion.c
> > > index f31e8c3f8ce0..eab3f2e6b786 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_opregion.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_opregion.c
> > > @@ -53,6 +53,8 @@
> > > #define MBOX_ASLE_EXT BIT(4) /* Mailbox #5 */
> > > #define MBOX_BACKLIGHT BIT(5) /* Mailbox #2
> > > (valid from v3.x) */
> > >
> > > +#define PCON_HEADLESS_SKU BIT(13)
> >
> > Here we go again.
> >
> > What does headless mean here? The spec does not say. Does it have
> > display hardware? Apparently yes, since otherwise we wouldn't be
> > here.
>
> This is for hybrid setup with several display hw and the panel wont be
> connected into device driven by i915 driver.
>
> > We have INTEL_DISPLAY_ENABLED() which should do the right thing when
> > you
> > do have display hardware and have done output setup etc. but want to
> > force them disconnected, i.e. you take the hardware over properly,
> > but
> > put it to sleep for power savings.
> >
> > Maybe we should bolt this opregion check in that macro?
> >
> > Maybe we need to use INTEL_DISPLAY_ENABLED() also to prevent polling.
>
> Thank you for pointing this out. HAS_DISPLAY I already notice and it's
> not suitable for what we want here. I think bolting this check into
> INTEL_DISPLAY_ENABLED as you suggested is enough. That will prevent
> waking up the hw into D0 state for polling.
A headless sku should not have any DDI ports enabled, much easier check for that.
>
> >
> > I certainly would not want to add another mode that's separate from
> > HAS_DISPLAY() and INTEL_DISPLAY_ENABLED().
>
> No need for this. I think we can go with INTEL_DISPLAY_ENABLED.
> >
> > > +
> > > struct opregion_header {
> > > u8 signature[16];
> > > u32 size;
> > > @@ -1135,6 +1137,16 @@ struct edid *intel_opregion_get_edid(struct
> > > intel_connector *intel_connector)
> > > return new_edid;
> > > }
> > >
> > > +bool intel_opregion_headless_sku(struct drm_i915_private *i915)
> > > +{
> > > + struct intel_opregion *opregion = &i915->opregion;
> > > +
> > > + if (!opregion->header)
> > > + return false;
> > > +
> > > + return opregion->header->pcon & PCON_HEADLESS_SKU;
> >
> > We should probably start checking for opregion version for this stuff
> > too.
> >
>
> Yes, I will do this change.
>
> >
> > BR,
> > Jani.
> >
> > > +}
> > > +
> > > void intel_opregion_register(struct drm_i915_private *i915)
> > > {
> > > struct intel_opregion *opregion = &i915->opregion;
> > > diff --git a/drivers/gpu/drm/i915/display/intel_opregion.h
> > > b/drivers/gpu/drm/i915/display/intel_opregion.h
> > > index 82cc0ba34af7..5ad96e1d8278 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_opregion.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_opregion.h
> > > @@ -76,6 +76,8 @@ int intel_opregion_notify_adapter(struct
> > > drm_i915_private *dev_priv,
> > > int intel_opregion_get_panel_type(struct drm_i915_private
> > > *dev_priv);
> > > struct edid *intel_opregion_get_edid(struct intel_connector
> > > *connector);
> > >
> > > +bool intel_opregion_headless_sku(struct drm_i915_private *i915);
> > > +
> > > #else /* CONFIG_ACPI*/
> > >
> > > static inline int intel_opregion_setup(struct drm_i915_private
> > > *dev_priv)
> > > @@ -127,6 +129,11 @@ intel_opregion_get_edid(struct intel_connector
> > > *connector)
> > > return NULL;
> > > }
> > >
> > > +bool intel_opregion_headless_sku(struct drm_i915_private *i915)
> > > +{
> > > + return false;
> > > +}
> > > +
> > > #endif /* CONFIG_ACPI */
> > >
> > > #endif
>
