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 <[email protected]>
> Cc: Imre Deak <[email protected]>
> Cc: Rodrigo Vivi <[email protected]>
> Cc: Clint Taylor <[email protected]>
>
> Signed-off-by: Dhinakaran Pandiyan <[email protected]>
>
> 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
>
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