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

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 31 Aug 2020, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> 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.

It's the least intrusive way to make this work across the drm and driver
EDID code that I could think of.

BR,
Jani.


>
> 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@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@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
>> 
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Graphics Center
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