[Intel-gfx] [PATCH 1/2] drm/i915/opregion: add support for mailbox #5 EDID

[Ville Syrjälä]

On Fri, Aug 28, 2020 at 09:19:40AM +0300, Jani Nikula wrote:
> The ACPI OpRegion Mailbox #5 ASLE extension may contain an EDID to be
> used for the embedded display. Add support for using it via the EDID
> override mechanism.

Abusing the override for this feels a bit odd.

Also I have a vague recollection that there was perhaps some
linkage between the mailbox and the ACPI _DDC stuff:
git://github.com/vsyrjala/linux.git acpi_edid

> 
> Note that the override EDID may be later reset or changed via debugfs,
> as usual.
> 
> Cc: Uma Shankar <uma.shankar at intel.com>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_opregion.c | 46 ++++++++++++++++++-
>  drivers/gpu/drm/i915/display/intel_opregion.h |  8 ++++
>  2 files changed, 53 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
> index de995362f428..13485969fafa 100644
> --- a/drivers/gpu/drm/i915/display/intel_opregion.c
> +++ b/drivers/gpu/drm/i915/display/intel_opregion.c
> @@ -196,6 +196,8 @@ struct opregion_asle_ext {
>  #define ASLE_IUER_WINDOWS_BTN		(1 << 1)
>  #define ASLE_IUER_POWER_BTN		(1 << 0)
>  
> +#define ASLE_PHED_EDID_VALID_MASK	0x3
> +
>  /* Software System Control Interrupt (SWSCI) */
>  #define SWSCI_SCIC_INDICATOR		(1 << 0)
>  #define SWSCI_SCIC_MAIN_FUNCTION_SHIFT	1
> @@ -909,8 +911,10 @@ int intel_opregion_setup(struct drm_i915_private *dev_priv)
>  		opregion->asle->ardy = ASLE_ARDY_NOT_READY;
>  	}
>  
> -	if (mboxes & MBOX_ASLE_EXT)
> +	if (mboxes & MBOX_ASLE_EXT) {
>  		drm_dbg(&dev_priv->drm, "ASLE extension supported\n");
> +		opregion->asle_ext = base + OPREGION_ASLE_EXT_OFFSET;
> +	}
>  
>  	if (intel_load_vbt_firmware(dev_priv) == 0)
>  		goto out;
> @@ -1041,6 +1045,45 @@ intel_opregion_get_panel_type(struct drm_i915_private *dev_priv)
>  	return ret - 1;
>  }
>  
> +void intel_opregion_edid_override(struct intel_connector *intel_connector)
> +{
> +	struct drm_connector *connector = &intel_connector->base;
> +	struct drm_i915_private *i915 = to_i915(connector->dev);
> +	struct intel_opregion *opregion = &i915->opregion;
> +	const void *in_edid;
> +	const struct edid *edid;
> +	int len, ret;
> +
> +	if (!opregion->asle_ext)
> +		return;
> +
> +	in_edid = opregion->asle_ext->bddc;
> +
> +	/* Validity corresponds to number of 128-byte blocks */
> +	len = (opregion->asle_ext->phed & ASLE_PHED_EDID_VALID_MASK) * 128;
> +	if (!len || !memchr_inv(in_edid, 0, len))
> +		return;
> +
> +	edid = in_edid;
> +
> +	/*
> +	 * FIXME: Might also check drm_edid_is_valid(edid) here but that
> +	 * requires mutable edid.
> +	 */
> +	if (len < EDID_LENGTH * (1 + edid->extensions)) {
> +		drm_dbg_kms(&i915->drm, "Invalid EDID in ACPI OpRegion (Mailbox #5)\n");
> +		return;
> +	}
> +
> +	connector->override_edid = false;
> +	ret = drm_connector_update_edid_property(connector, edid);
> +	if (ret)
> +		return;
> +
> +	drm_dbg_kms(&i915->drm, "Using OpRegion EDID for [CONNECTOR:%d:%s]\n",
> +		    connector->base.id, connector->name);
> +}
> +
>  void intel_opregion_register(struct drm_i915_private *i915)
>  {
>  	struct intel_opregion *opregion = &i915->opregion;
> @@ -1131,6 +1174,7 @@ void intel_opregion_unregister(struct drm_i915_private *i915)
>  	opregion->acpi = NULL;
>  	opregion->swsci = NULL;
>  	opregion->asle = NULL;
> +	opregion->asle_ext = NULL;
>  	opregion->vbt = NULL;
>  	opregion->lid_state = NULL;
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_opregion.h b/drivers/gpu/drm/i915/display/intel_opregion.h
> index 4aa68ffbd30e..b407a0744c40 100644
> --- a/drivers/gpu/drm/i915/display/intel_opregion.h
> +++ b/drivers/gpu/drm/i915/display/intel_opregion.h
> @@ -29,12 +29,14 @@
>  #include <linux/pci.h>
>  
>  struct drm_i915_private;
> +struct intel_connector;
>  struct intel_encoder;
>  
>  struct opregion_header;
>  struct opregion_acpi;
>  struct opregion_swsci;
>  struct opregion_asle;
> +struct opregion_asle_ext;
>  
>  struct intel_opregion {
>  	struct opregion_header *header;
> @@ -43,6 +45,7 @@ struct intel_opregion {
>  	u32 swsci_gbda_sub_functions;
>  	u32 swsci_sbcb_sub_functions;
>  	struct opregion_asle *asle;
> +	struct opregion_asle_ext *asle_ext;
>  	void *rvda;
>  	void *vbt_firmware;
>  	const void *vbt;
> @@ -71,6 +74,7 @@ int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
>  int intel_opregion_notify_adapter(struct drm_i915_private *dev_priv,
>  				  pci_power_t state);
>  int intel_opregion_get_panel_type(struct drm_i915_private *dev_priv);
> +void intel_opregion_edid_override(struct intel_connector *connector);
>  
>  #else /* CONFIG_ACPI*/
>  
> @@ -117,6 +121,10 @@ static inline int intel_opregion_get_panel_type(struct drm_i915_private *dev)
>  	return -ENODEV;
>  }
>  
> +void intel_opregion_edid_override(struct intel_connector *connector)
> +{
> +}
> +
>  #endif /* CONFIG_ACPI */
>  
>  #endif
> -- 
> 2.20.1
> 
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> Intel-gfx at lists.freedesktop.org
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-- 
Ville Syrjälä
Intel