[Intel-gfx] [v2 6/6] drm/i915/fec: Disable FEC state.

[Srivatsa, Anusha]

>-----Original Message-----
>From: Navare, Manasi D
>Sent: Thursday, October 18, 2018 4:16 PM
>To: Srivatsa, Anusha <anusha.srivatsa at intel.com>
>Cc: intel-gfx at lists.freedesktop.org; Singh, Gaurav K <gaurav.k.singh at intel.com>;
>Jani Nikula <jani.nikula at linux.intel.com>; Ville Syrjala
><ville.syrjala at linux.intel.com>
>Subject: Re: [v2 6/6] drm/i915/fec: Disable FEC state.
>
>Hi Anusha,
>
>Find my comments below:
>
>On Mon, Oct 15, 2018 at 02:50:37PM -0700, Anusha Srivatsa wrote:
>> Set the suitable bits in DP_TP_CTL to stop bit correction when DSC is
>> disabled.
>>
>
>> - rebased.
>> - Add additional check for compression state. (Gaurav)
>>
>> v3: rebased.
>>
>> Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>> Cc: Manasi Navare <manasi.d.navare at intel.com>
>> Signed-off-by: Anusha Srivatsa <anusha.srivatsa at intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_ddi.c |  2 ++
>> drivers/gpu/drm/i915/intel_dp.c  | 18 ++++++++++++++++++
>> drivers/gpu/drm/i915/intel_drv.h |  2 ++
>>  3 files changed, 22 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_ddi.c
>> b/drivers/gpu/drm/i915/intel_ddi.c
>> index 67c013ea4d39..fefa92070b2d 100644
>> --- a/drivers/gpu/drm/i915/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/intel_ddi.c
>> @@ -3245,6 +3245,8 @@ static void intel_disable_ddi_dp(struct intel_encoder
>*encoder,
>>  	/* Disable the decompression in DP Sink */
>>  	intel_dp_sink_set_decompression_state(intel_dp, old_crtc_state,
>>  					      ~DP_DECOMPRESSION_EN);
>> +	/* Disable FEC in DP Sink */
>> +	intel_dp_disable_fec_state(intel_dp, old_crtc_state);
>>  }
>>
>>  static void intel_disable_ddi_hdmi(struct intel_encoder *encoder,
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c
>> b/drivers/gpu/drm/i915/intel_dp.c index b9f85502d9ff..1db1a738c85f
>> 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -3044,6 +3044,24 @@ void intel_dp_enable_fec_state(struct intel_dp
>*intel_dp,
>>  		DRM_ERROR("Timed out waiting for FEC Enable Status\n");  }
>>
>> +void intel_dp_disable_fec_state(struct intel_dp *intel_dp,
>> +				const struct intel_crtc_state *crtc_state) {
>> +	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
>> +	enum port port = intel_dig_port->base.port;
>> +	u32 val;
>> +
>> +	if (crtc_state->dsc_params.compression_enable)
>> +		DRM_DEBUG_KMS("Compression still enabled\n");
>
>This check is wrong. The crtc_state->dsc_params.compression_enable only
>indicates that compression enable is allowed in atomic check. This does not
>indicate whether it is enabled or disabled in source/sink
>
>Infact this function shd return if !crtc_state->dsc_params.compression_enable,
>see what intel_dp_sink_set_decompression_state does.
>
>After that to make sure DSC is disabled, you can read DP_DSC_ENABLE DPCD
>register and check DP_DECOMPRESSION_EN bit before proceeding to disabling
>FEC.

That is a good point. I will make the changes. 
Thanks For the review.

Anusha 
>Manasi
>
>> +		return;
>> +
>> +	val = I915_READ(DP_TP_CTL(port));
>> +	val &= ~DP_TP_CTL_FEC_ENABLE;
>> +	I915_WRITE(DP_TP_CTL(port), val);
>> +	POSTING_READ(DP_TP_CTL(port));
>> +}
>> +
>>  /* If the sink supports it, try to set the power state appropriately
>> */  void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)  {
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h
>> b/drivers/gpu/drm/i915/intel_drv.h
>> index e51d612a9f42..0c2429f7cc35 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -1713,6 +1713,8 @@ void intel_dp_sink_set_fec_ready(struct intel_dp
>*intel_dp,
>>  				 int state);
>>  void intel_dp_enable_fec_state(struct intel_dp *intel_dp,
>>  			       const struct intel_crtc_state *crtc_state);
>> +void intel_dp_disable_fec_state(struct intel_dp *intel_dp,
>> +				const struct intel_crtc_state *crtc_state);
>>  void intel_dp_encoder_reset(struct drm_encoder *encoder);  void
>> intel_dp_encoder_suspend(struct intel_encoder *intel_encoder);  void
>> intel_dp_encoder_destroy(struct drm_encoder *encoder);
>> --
>> 2.17.1
>>