Re: [PATCH v3] drm/i915/mst: Use MST sideband message transactions for dpms control

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

On Tue, 03 Oct 2017, Jani Nikula <jani.nikula@intel.com> wrote:
> From: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
>
> Use the POWER_DOWN_PHY and POWER_UP_PHY sideband message transactions to
> set power states for downstream sinks. Apart from giving us the ability
> to set power state for individual sinks, this fixes the below test for
> me.
>
> $ xrandr --display :0 --output DP-2-2-8 --off
> $ xrandr --display :0 --output DP-2-2-1 --off
> $ xrandr --display :0 --output DP-2-2-8 --auto #Black screen
> $ xrandr --display :0 --output DP-2-2-1 --auto
>
> v2: Modify and document the dpms and port disable order (Ville)
>     Add comment explaining is_mst = !crtc_state equivalence(Ville, Maarten)
>
> v3 by Jani: rebase
>
> References: https://bugs.freedesktop.org/show_bug.cgi?id=90963
> References: https://bugs.freedesktop.org/show_bug.cgi?id=88124
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Lyude <lyude@redhat.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Reviewed-by: Lyude Paul <lyude@redhat.com>
> Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

Lyude, Maarten, can you confirm your rb/ack on my rebase please?

BR,
Jani.


> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_ddi.c    | 18 ++++++++++++++----
>  drivers/gpu/drm/i915/intel_dp_mst.c | 10 ++++++++--
>  2 files changed, 22 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 65f4b6786791..511aa60e0176 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -2162,7 +2162,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
>  		intel_prepare_dp_ddi_buffers(encoder);
>  
>  	intel_ddi_init_dp_buf_reg(encoder);
> -	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
> +	if (!link_mst)
> +		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
>  	intel_dp_start_link_train(intel_dp);
>  	if (port != PORT_A || INTEL_GEN(dev_priv) >= 9)
>  		intel_dp_stop_link_train(intel_dp);
> @@ -2236,12 +2237,21 @@ static void intel_ddi_post_disable(struct intel_encoder *intel_encoder,
>  	uint32_t val;
>  	bool wait = false;
>  
> -	/* old_crtc_state and old_conn_state are NULL when called from DP_MST */
> -
>  	if (type == INTEL_OUTPUT_DP || type == INTEL_OUTPUT_EDP) {
> +		/*
> +		 * old_crtc_state and old_conn_state are NULL when called from
> +		 * DP_MST. The main connector associated with this port is never
> +		 * bound to a crtc for MST.
> +		 */
> +		bool is_mst = !old_crtc_state;
>  		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  
> -		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
> +		/*
> +		 * Power down sink before disabling the port, otherwise we end
> +		 * up getting interrupts from the sink on detecting link loss.
> +		 */
> +		if (!is_mst)
> +			intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
>  	}
>  
>  	val = I915_READ(DDI_BUF_CTL(port));
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index 9a396f483f8b..3c131e2544cf 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -162,14 +162,19 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
>  
>  	drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, connector->port);
>  
> +	/*
> +	 * Power down mst path before disabling the port, otherwise we end
> +	 * up getting interrupts from the sink upon detecting link loss.
> +	 */
> +	drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector->port,
> +				     false);
> +
>  	intel_dp->active_mst_links--;
>  
>  	intel_mst->connector = NULL;
>  	if (intel_dp->active_mst_links == 0) {
>  		intel_dig_port->base.post_disable(&intel_dig_port->base,
>  						  NULL, NULL);
> -
> -		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
>  	}
>  	DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
>  }
> @@ -196,6 +201,7 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
>  
>  	DRM_DEBUG_KMS("active links %d\n", intel_dp->active_mst_links);
>  
> +	drm_dp_send_power_updown_phy(&intel_dp->mst_mgr, connector->port, true);
>  	if (intel_dp->active_mst_links == 0)
>  		intel_dig_port->base.pre_enable(&intel_dig_port->base,
>  						pipe_config, NULL);

-- 
Jani Nikula, Intel Open Source Technology Center
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