Re: [Intel-gfx] [PATCH 1/3] drm/i915: disable all display features when no display

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

On Thu, 10 Sep 2020, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Thu, Sep 10, 2020 at 12:52:25PM +0300, Jani Nikula wrote:
>> Disable all display feature flags when there are no pipes i.e. there is
>> no display. This should help with not having to additionally check for
>> HAS_DISPLAY() when a feature flag check would suffice.
>> 
>> Also disable modeset and atomic driver features.
>
> While bspec is rather vague whether this is actually entirely consistent
> with how th hw works, it seems rather silly if any display hw blocks
> would get initialized by the BIOS/whatever when there are no usable
> pipes.
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Pushed the lot, thanks for the reviews.

BR,
Jani.

>
>> 
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_device_info.c | 8 ++++++++
>>  1 file changed, 8 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
>> index e2aa5bc3a6e0..adc836f15fde 100644
>> --- a/drivers/gpu/drm/i915/intel_device_info.c
>> +++ b/drivers/gpu/drm/i915/intel_device_info.c
>> @@ -516,6 +516,14 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
>>  					    S32_MAX),
>>  				USEC_PER_SEC));
>>  	}
>> +
>> +	if (!HAS_DISPLAY(dev_priv)) {
>> +		dev_priv->drm.driver_features &= ~(DRIVER_MODESET |
>> +						   DRIVER_ATOMIC);
>> +		memset(&info->display, 0, sizeof(info->display));
>> +		memset(runtime->num_sprites, 0, sizeof(runtime->num_sprites));
>> +		memset(runtime->num_scalers, 0, sizeof(runtime->num_scalers));
>
> Side note: No idea why the num_scalers/sprites is stored under the
> runtime info. I think those could just live in the normal PCI ID
> based device info.
>
>> +	}
>>  }
>>  
>>  void intel_driver_caps_print(const struct intel_driver_caps *caps,
>> -- 
>> 2.20.1

-- 
Jani Nikula, Intel Open Source Graphics Center
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