Re: [Intel-gfx] [PATCH 1/3] drm/i915/display: move vbt check to intel_ddi_init()

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

On Mon, 15 Feb 2021, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> On Mon, Feb 15, 2021 at 12:35:50PM +0200, Jani Nikula wrote:
>>On Sat, 13 Feb 2021, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
>>> On intel_ddi_init() we already check VBT if the port supports HDMI/DP
>>> and bail out otherwise. Instad of checking if a single port is present
>>> using VBT in intel_display.c, move the stronger check to
>>> intel_ddi_init() and return early in case it's not supported.  There
>>> would be no way intel_bios_* would report support for hdmi/dp if the
>>> port isn't present so this should cause no regressions for other
>>> platforms.
>>
>>Sorry, but this will regress machines that have no VBT.
>
> I missed that init_vbt_missing_defaults() also sets
> the supports_*.
>
>>
>>I've been thinking about creating fake child devices for that case to
>>reduce the exceptions.
>
> Adding a fake child would indeed be a good option. Are you going to
> implement that soon or should I?

I'm working on it. Got a bit carried away with what I've had in mind for
ages regarding some other refactoring (e.g. getting rid of
i915->vbt.ddi_port_info[] altogether in order to bring pre- and post-ddi
platforms closer together). I'll try to get a smaller set ready first.

BR,
Jani.


>
> thanks
> Lucas De Marchi
>
>>
>>BR,
>>Jani.
>>
>>
>>
>>>
>>> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
>>> ---
>>>  drivers/gpu/drm/i915/display/intel_ddi.c     |  7 +++++++
>>>  drivers/gpu/drm/i915/display/intel_display.c | 14 ++++++--------
>>>  2 files changed, 13 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
>>> index 3b97c0091812..1235be0ba5d1 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>>> @@ -3972,6 +3972,13 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
>>>  	bool init_hdmi, init_dp;
>>>  	enum phy phy = intel_port_to_phy(dev_priv, port);
>>>
>>> +	if (!intel_bios_is_port_present(dev_priv, port)) {
>>> +		drm_dbg_kms(&dev_priv->drm,
>>> +			    "VBT says port %c is not present, respect it\n",
>>> +			    port_name(port));
>>> +		return;
>>> +	}
>>> +
>>>  	/*
>>>  	 * On platforms with HTI (aka HDPORT), if it's enabled at boot it may
>>>  	 * have taken over some of the PHYs and made them unavailable to the
>>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>>> index 23ec68498800..7aaf7a29d493 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>>> @@ -11904,13 +11904,13 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
>>>  		intel_ddi_init(dev_priv, PORT_C);
>>>  		intel_ddi_init(dev_priv, PORT_D);
>>>  		intel_ddi_init(dev_priv, PORT_E);
>>> +
>>>  		/*
>>> -		 * On some ICL SKUs port F is not present. No strap bits for
>>> -		 * this, so rely on VBT.
>>> -		 * Work around broken VBTs on SKUs known to have no port F.
>>> +		 * On some ICL SKUs port F is not present, but broken VBTs mark
>>> +		 * the port as present. Only try to initialize port F for the
>>> +		 * SKUs that may actually have it.
>>>  		 */
>>> -		if (IS_ICL_WITH_PORT_F(dev_priv) &&
>>> -		    intel_bios_is_port_present(dev_priv, PORT_F))
>>> +		if (IS_ICL_WITH_PORT_F(dev_priv))
>>>  			intel_ddi_init(dev_priv, PORT_F);
>>>
>>>  		icl_dsi_init(dev_priv);
>>> @@ -11964,10 +11964,8 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
>>>  		/*
>>>  		 * On SKL we don't have a way to detect DDI-E so we rely on VBT.
>>>  		 */
>>> -		if (IS_GEN9_BC(dev_priv) &&
>>> -		    intel_bios_is_port_present(dev_priv, PORT_E))
>>> +		if (IS_GEN9_BC(dev_priv))
>>>  			intel_ddi_init(dev_priv, PORT_E);
>>> -
>>>  	} else if (HAS_PCH_SPLIT(dev_priv)) {
>>>  		int found;
>>
>>-- 
>>Jani Nikula, Intel Open Source Graphics Center

-- 
Jani Nikula, Intel Open Source Graphics Center
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