[Intel-gfx] [PATCH 2/3] drm/i915/dp: Restrict link retrain workaround to external monitors

[Ville Syrjälä]

On Thu, Sep 06, 2018 at 11:21:34PM -0700, Dhinakaran Pandiyan wrote:
> commit '3cf71bc9904d ("drm/i915: Re-apply "Perform link quality check,
> unconditionally during long pulse"")' applies a work around for monitors
> that don't signal link loss. Apply this only for external displays as
> eDP features like PSR when active will have the link turned off and the
> driver ends up retraining the link seeeing that link is not synchronized.
> 
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: Jan-Marek Glogowski <glogow at fbihome.de>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> References: 3cf71bc9904d ("drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse"")
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index befdaa076d8c..c59b2f78f41a 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5072,7 +5072,9 @@ intel_dp_full_detect(struct intel_connector *connector,
>  		 */
>  		status = connector_status_disconnected;
>  		goto out;
> -	} else {
> +	}
> +
> +	if (!intel_dp_is_edp(intel_dp)) {

Hmm. How do things work if we get a short hpd from the sink while it's
in PSR link off mode? Won't we try to retrain in that case as well?

>  		/*
>  		 * Check link status in case the link went out of
>  		 * synchronization and the sink did not tell us.
> -- 
> 2.17.1

-- 
Ville Syrjälä
Intel