Re: [PATCH v5 2/2] drm/i915: State readout and cross-checking for dp_m2_n2

[Vandana Kannan <vandana.kannan@intel.com>]

On Jun-13-2014 7:42 PM, Jani Nikula wrote:
> On Thu, 22 May 2014, Vandana Kannan <vandana.kannan@intel.com> wrote:
>> Adding relevant read out comparison code, in check_crtc_state, for the new
>> member of crtc_config, dp_m2_n2, which was introduced to store link_m_n
>> values for a DP downclock mode (if available). Suggested by Daniel.
>>
>> v2: Changed patch title.
>> Daniel's review comments incorporated.
>> Added relevant state readout code for M2_N2. dp_m2_n2 comparison to be done
>> only when high RR is not in use (This is because alternate m_n register
>> programming will be done only when low RR is being used).
>>
>> v3: Modified call to get_m2_n2 which had dp_m_n as param by mistake.
>> Compare dp_m_n and dp_m2_n2 for gen 7 and below. compare the structures
>> based on DRRS state for gen 8 and above.
>> Save and restore M2 N2 registers for gen 7 and below
>>
>> v4: For Gen>=8, check M_N registers against dp_m_n and dp_m2_n2 as there is
>> only one set of M_N registers
>>
>> v5: Removed the chunk which saves and restores M2_N2 registers. Modified
>> get_m_n() to get M2_N2 registers as well. Modified the macro which compares
>> hw.dp_m_n against sw.dp_m2_n2/sw.dp_m_n for gen > 8.
>>
>> Signed-off-by: Vandana Kannan <vandana.kannan@intel.com>
>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>> ---
>>  drivers/gpu/drm/i915/intel_display.c | 68 +++++++++++++++++++++++++++++++-----
>>  1 file changed, 60 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index cf3ad87..d593897 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -6945,7 +6945,8 @@ static void intel_pch_transcoder_get_m_n(struct intel_crtc *crtc,
>>  
>>  static void intel_cpu_transcoder_get_m_n(struct intel_crtc *crtc,
>>  					 enum transcoder transcoder,
>> -					 struct intel_link_m_n *m_n)
>> +					 struct intel_link_m_n *m_n,
>> +					 struct intel_link_m_n *m2_n2)
>>  {
>>  	struct drm_device *dev = crtc->base.dev;
>>  	struct drm_i915_private *dev_priv = dev->dev_private;
>> @@ -6959,6 +6960,15 @@ static void intel_cpu_transcoder_get_m_n(struct intel_crtc *crtc,
>>  		m_n->gmch_n = I915_READ(PIPE_DATA_N1(transcoder));
>>  		m_n->tu = ((I915_READ(PIPE_DATA_M1(transcoder))
>>  			    & TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
>> +		if (m2_n2 && INTEL_INFO(dev)->gen < 8) {
>> +			m2_n2->link_m = I915_READ(PIPE_LINK_M2(transcoder));
>> +			m2_n2->link_n =	I915_READ(PIPE_LINK_N2(transcoder));
>> +			m2_n2->gmch_m =	I915_READ(PIPE_DATA_M2(transcoder))
>> +					& ~TU_SIZE_MASK;
>> +			m2_n2->gmch_n =	I915_READ(PIPE_DATA_N2(transcoder));
>> +			m2_n2->tu = ((I915_READ(PIPE_DATA_M2(transcoder))
>> +					& TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
>> +		}
>>  	} else {
>>  		m_n->link_m = I915_READ(PIPE_LINK_M_G4X(pipe));
>>  		m_n->link_n = I915_READ(PIPE_LINK_N_G4X(pipe));
>> @@ -6977,14 +6987,15 @@ void intel_dp_get_m_n(struct intel_crtc *crtc,
>>  		intel_pch_transcoder_get_m_n(crtc, &pipe_config->dp_m_n);
>>  	else
>>  		intel_cpu_transcoder_get_m_n(crtc, pipe_config->cpu_transcoder,
>> -					     &pipe_config->dp_m_n);
>> +					     &pipe_config->dp_m_n,
>> +					     &pipe_config->dp_m2_n2);
>>  }
>>  
>>  static void ironlake_get_fdi_m_n_config(struct intel_crtc *crtc,
>>  					struct intel_crtc_config *pipe_config)
>>  {
>>  	intel_cpu_transcoder_get_m_n(crtc, pipe_config->cpu_transcoder,
>> -				     &pipe_config->fdi_m_n);
>> +				     &pipe_config->fdi_m_n, NULL);
>>  }
>>  
>>  static void ironlake_get_pfit_config(struct intel_crtc *crtc,
>> @@ -9485,6 +9496,15 @@ static void intel_dump_pipe_config(struct intel_crtc *crtc,
>>  		      pipe_config->dp_m_n.gmch_m, pipe_config->dp_m_n.gmch_n,
>>  		      pipe_config->dp_m_n.link_m, pipe_config->dp_m_n.link_n,
>>  		      pipe_config->dp_m_n.tu);
>> +
>> +	DRM_DEBUG_KMS("dp: %i, gmch_m2: %u, gmch_n2: %u, link_m2: %u, link_n2: %u, tu2: %u\n",
>> +		      pipe_config->has_dp_encoder,
>> +		      pipe_config->dp_m2_n2.gmch_m,
>> +		      pipe_config->dp_m2_n2.gmch_n,
>> +		      pipe_config->dp_m2_n2.link_m,
>> +		      pipe_config->dp_m2_n2.link_n,
>> +		      pipe_config->dp_m2_n2.tu);
>> +
>>  	DRM_DEBUG_KMS("requested mode:\n");
>>  	drm_mode_debug_printmodeline(&pipe_config->requested_mode);
>>  	DRM_DEBUG_KMS("adjusted mode:\n");
>> @@ -9867,6 +9887,22 @@ intel_pipe_config_compare(struct drm_device *dev,
>>  		return false; \
>>  	}
>>  
>> +/* This is required for BDW+ where there is only one set of registers for
>> + * switching between high and low RR.
>> + * This macro can be used whenever a comparison has to be made between one
>> + * hw state and multiple sw state variables.
>> + */
>> +#define PIPE_CONF_CHECK_I_ALT(name, alt_name) \
>> +	if ((current_config->name != pipe_config->name) && \
>> +		(current_config->alt_name != pipe_config->name)) { \
>> +			DRM_ERROR("mismatch in " #name " " \
>> +				  "(expected %i or %i, found %i)\n", \
>> +				  current_config->name, \
>> +				  current_config->alt_name, \
>> +				  pipe_config->name); \
>> +			return false; \
>> +	}
>> +
>>  #define PIPE_CONF_CHECK_FLAGS(name, mask)	\
>>  	if ((current_config->name ^ pipe_config->name) & (mask)) { \
>>  		DRM_ERROR("mismatch in " #name "(" #mask ") "	   \
>> @@ -9899,11 +9935,26 @@ intel_pipe_config_compare(struct drm_device *dev,
>>  	PIPE_CONF_CHECK_I(fdi_m_n.tu);
>>  
>>  	PIPE_CONF_CHECK_I(has_dp_encoder);
>> -	PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
>> -	PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
>> -	PIPE_CONF_CHECK_I(dp_m_n.link_m);
>> -	PIPE_CONF_CHECK_I(dp_m_n.link_n);
>> -	PIPE_CONF_CHECK_I(dp_m_n.tu);
>> +
>> +	if (INTEL_INFO(dev)->gen < 8) {
>> +		PIPE_CONF_CHECK_I(dp_m_n.gmch_m);
>> +		PIPE_CONF_CHECK_I(dp_m_n.gmch_n);
>> +		PIPE_CONF_CHECK_I(dp_m_n.link_m);
>> +		PIPE_CONF_CHECK_I(dp_m_n.link_n);
>> +		PIPE_CONF_CHECK_I(dp_m_n.tu);
>> +
>> +		PIPE_CONF_CHECK_I(dp_m2_n2.gmch_m);
>> +		PIPE_CONF_CHECK_I(dp_m2_n2.gmch_n);
>> +		PIPE_CONF_CHECK_I(dp_m2_n2.link_m);
>> +		PIPE_CONF_CHECK_I(dp_m2_n2.link_n);
>> +		PIPE_CONF_CHECK_I(dp_m2_n2.tu);
>> +	} else {
>> +		PIPE_CONF_CHECK_I_ALT(dp_m_n.gmch_m, dp_m2_n2.gmch_m);
>> +		PIPE_CONF_CHECK_I_ALT(dp_m_n.gmch_n, dp_m2_n2.gmch_n);
>> +		PIPE_CONF_CHECK_I_ALT(dp_m_n.link_m, dp_m2_n2.link_m);
>> +		PIPE_CONF_CHECK_I_ALT(dp_m_n.link_n, dp_m2_n2.link_n);
>> +		PIPE_CONF_CHECK_I_ALT(dp_m_n.tu, dp_m2_n2.tu);
> 
> If there's no downclock mode (e.g. because it's not eDP), this now
> accepts register value 0 as okay for each state check. That's not cool.
> 
> Perhaps drrs state should be part of pipe config.
> 
> BR,
> Jani.
> 
Ok, shall I go ahead with the following approach?

pipe_config{
	drrs_state;
}

in pipe_config_compare() {
if gen < 8 {
compare dp_m1_n1
if drrs_state == seamless
	compare hw.dp_m2_n2 and sw.dp_m2_n2
/* this drrs_state would be set only in edp_init_connector and only when
a downclock_mode is found */
}
else
	compare hw.dp_m_n and sw.dp_m_n or sw.dp_m2_n2
}

drrs_state is stored in vbt struct and intel_dp as of now. some changes
would be required around this to avoid saving this state at a third
place (pipe_config).
option 1. move drrs_state from intel_dp to dev_priv.
option 2. move drrs_state from intel_dp to pipe_config.

with the above changes, the patches accessing intel_dp->drrs_state would
require changes.

Please let me know your inputs on this.

-Vandana


> 
> 
> 
> 
> 
> 
>> +	}
>>  
>>  	PIPE_CONF_CHECK_I(adjusted_mode.crtc_hdisplay);
>>  	PIPE_CONF_CHECK_I(adjusted_mode.crtc_htotal);
>> @@ -9980,6 +10031,7 @@ intel_pipe_config_compare(struct drm_device *dev,
>>  
>>  #undef PIPE_CONF_CHECK_X
>>  #undef PIPE_CONF_CHECK_I
>> +#undef PIPE_CONF_CHECK_I_ALT
>>  #undef PIPE_CONF_CHECK_FLAGS
>>  #undef PIPE_CONF_CHECK_CLOCK_FUZZY
>>  #undef PIPE_CONF_QUIRK
>> -- 
>> 1.9.3
>>
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>