[Intel-gfx] [PATCH] drm/i915/dp_mst: Fix enabling pipe clock for all streams

[Ville Syrjälä]

On Fri, Aug 31, 2018 at 08:47:39PM +0300, Imre Deak wrote:
> commit afb2c4437dae ("drm/i915/ddi: Push pipe clock enabling to encoders")
> inadvertently stopped enabling the pipe clock for any DP-MST stream
> after the first one. It also rearranged the pipe clock enabling wrt.
> initial MST payload allocation step (which may or may not be a
> problem, but it's contrary to the spec.).
> 
> Fix things by making the above commit truly a non-functional change.
> 
> Fixes: commit afb2c4437dae ("drm/i915/ddi: Push pipe clock enabling to encoders")
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107365
> Reported-by: Lyude Paul <lyude at redhat.com>
> Reported-by: dmummenschanz at web.de
> Tested-by: dmummenschanz at web.de
> Cc: Lyude Paul <lyude at redhat.com>
> Cc: dmummenschanz at web.de
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/intel_ddi.c    | 17 +++++++++--------
>  drivers/gpu/drm/i915/intel_dp_mst.c |  4 ++++
>  2 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index f3b115ce4029..dcb1a98d624d 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -2912,7 +2912,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
>  
>  	icl_enable_phy_clock_gating(dig_port);
>  
> -	intel_ddi_enable_pipe_clock(crtc_state);
> +	if (!is_mst)
> +		intel_ddi_enable_pipe_clock(crtc_state);
>  }
>  
>  static void intel_ddi_pre_enable_hdmi(struct intel_encoder *encoder,
> @@ -3015,14 +3016,14 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder,
>  	bool is_mst = intel_crtc_has_type(old_crtc_state,
>  					  INTEL_OUTPUT_DP_MST);
>  
> -	intel_ddi_disable_pipe_clock(old_crtc_state);
> -
> -	/*
> -	 * Power down sink before disabling the port, otherwise we end
> -	 * up getting interrupts from the sink on detecting link loss.
> -	 */
> -	if (!is_mst)
> +	if (!is_mst) {
> +		intel_ddi_disable_pipe_clock(old_crtc_state);
> +		/*
> +		 * Power down sink before disabling the port, otherwise we end
> +		 * up getting interrupts from the sink on detecting link loss.
> +		 */
>  		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
> +	}
>  
>  	intel_disable_ddi_buf(encoder);
>  
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index 352e5216cc65..77920f1a3da1 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -166,6 +166,8 @@ static void intel_mst_post_disable_dp(struct intel_encoder *encoder,
>  	struct intel_connector *connector =
>  		to_intel_connector(old_conn_state->connector);
>  
> +	intel_ddi_disable_pipe_clock(old_crtc_state);
> +
>  	/* this can fail */
>  	drm_dp_check_act_status(&intel_dp->mst_mgr);
>  	/* and this can also fail */
> @@ -249,6 +251,8 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
>  	I915_WRITE(DP_TP_STATUS(port), temp);
>  
>  	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
> +
> +	intel_ddi_enable_pipe_clock(pipe_config);
>  }
>  
>  static void intel_mst_enable_dp(struct intel_encoder *encoder,
> -- 
> 2.13.2

-- 
Ville Syrjälä
Intel