[Intel-gfx] [PATCH] drm/i915: Fix broken mst get_hw_state.

[Maarten Lankhorst]

Op 02-09-15 om 16:07 schreef Ander Conselvan De Oliveira:
> On Thu, 2015-08-27 at 13:13 +0200, Maarten Lankhorst wrote:
>> connector->encoder is initialized as NULL. Fix this by setting it in
>> during pre enable. MST connectors are not read out during initial hw
>> readout, and have no fixed encoder mappings. So it's harmless to
>> return false when the connector has never been assigned to an encoder.
>>    
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>> ---
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 738178a0ac96..e3922d973db0 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -6283,7 +6283,7 @@ static void intel_connector_check_state(struct intel_connector *connector)
>>  		      connector->base.name);
>>  
>>  	if (connector->get_hw_state(connector)) {
>> -		struct drm_encoder *encoder = &connector->encoder->base;
>> +		struct intel_encoder *encoder = connector->encoder;
>>  		struct drm_connector_state *conn_state = connector->base.state;
>>  
>>  		I915_STATE_WARN(!crtc,
>> @@ -6295,13 +6295,13 @@ static void intel_connector_check_state(struct intel_connector *connector)
>>  		I915_STATE_WARN(!crtc->state->active,
>>  		      "connector is active, but attached crtc isn't\n");
>>  
>> -		if (!encoder)
>> +		if (!encoder || encoder->type == INTEL_OUTPUT_DP_MST)
>>  			return;
>>  
>> -		I915_STATE_WARN(conn_state->best_encoder != encoder,
>> +		I915_STATE_WARN(conn_state->best_encoder != &encoder->base,
>>  			"atomic encoder doesn't match attached encoder\n");
>>  
>> -		I915_STATE_WARN(conn_state->crtc != encoder->crtc,
>> +		I915_STATE_WARN(conn_state->crtc != encoder->base.crtc,
>>  			"attached encoder crtc differs from connector crtc\n");
>>  	} else {
>>  		I915_STATE_WARN(crtc && crtc->state->active,
>> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
>> index ebf205462631..d606721b1788 100644
>> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
>> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
>> @@ -159,6 +159,11 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder)
>>  		return;
>>  	}
>>  
>> +	/* MST encoders are bound to a crtc, not to a connector,
>> +	 * force the mapping here for get_hw_state.
>> +	 */
>> +	found->encoder = encoder;
>> +
>>  	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
>>  	intel_mst->port = found->port;
>>  
>> @@ -392,7 +397,7 @@ static const struct drm_encoder_funcs intel_dp_mst_enc_funcs = {
>>  
>>  static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
>>  {
>> -	if (connector->encoder) {
>> +	if (connector->encoder && connector->base.state->crtc) {
> Is this here to cover the case where we disable this connector and assign the encoder to a different
> connector? I guess this should work since if we disable the connector than crtc will be null, and
> we'll assign a proper encoder when re-enabling. But now I'm wondering if it would make sense to set
> connector->encoder back to NULL in post_disable.
>
Yes, it's harmless to keep it non-null if conn_state->crtc is checked though. Saves another pointless loop.