[Intel-gfx] [PATCH] drm/i915/vbt: Assume port A is connected to eDP when there's no VBT

[Pandiyan, Dhinakaran]

On Thu, 2017-08-10 at 05:47 +0000, Navare, Manasi D wrote:
> We currently assume port A is connected to a DP sink when VBT is absent, instead assume it is connected to an eDP sink, which seems like a more common configuration. Although I don't have data to back this up, it is still just as valid as asumming port A is not eDP. This reverts to the behavior before a98d9c1 ("drm/i915/ddi: Rely on VBT DDI port info for eDP detection") except only when there is no VBT. Knowing whether a panel is eDP or not from the panel itself would have been nicer, but I cannot find any DPCD registers that provide this reliably.
> 
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Imre Deak <imre.deak at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Clint Taylor <clinton.a.taylor at intel.com>
> 
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> 
> Is this patch trying to fix a specific bug? 

Yes, we have a platform without vbt that has an eDP.

> Where do you plan to use supports_edp flag? 

No plans, this is not a new flag. The vbt info is used when when dp
connectors are initialized.

> I guess I am trying to understand the need for this in the vbt missing defaults and what this patch is trying to solve here. 

Assuming port A is not connected an eDP display when it actually is
messes up connector status detection. 


> 
> Manasi
> 
> 
> ---
>  drivers/gpu/drm/i915/intel_bios.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_bios.c b/drivers/gpu/drm/i915/intel_bios.c
> index 82b144c..89a405e 100644
> --- a/drivers/gpu/drm/i915/intel_bios.c
> +++ b/drivers/gpu/drm/i915/intel_bios.c
> @@ -1403,6 +1403,7 @@ init_vbt_missing_defaults(struct drm_i915_private *dev_priv)
>  		info->supports_dvi = (port != PORT_A && port != PORT_E);
>  		info->supports_hdmi = info->supports_dvi;
>  		info->supports_dp = (port != PORT_E);
> +		info->supports_edp = (port == PORT_A);
> 
>  	}
>  }
>  
> --
> 2.7.4
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx