Re: [PATCH 1/3] drm/i915: consider the source max DP lane count too

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

On Tue, 06 May 2014, Damien Lespiau <damien.lespiau@intel.com> wrote:
> On Tue, May 06, 2014 at 02:56:50PM +0300, Jani Nikula wrote:
>> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>> 
>> Even if the panel claims it can support 4 lanes, there's the
>> possibility that the HW can't, so consider this while selecting the
>> max lane count.
>> 
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>

Series pushed to -fixes, thanks for the swift review!

BR,
Jani.

>
> -- 
> Damien
>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 20 ++++++++++++++++++--
>>  1 file changed, 18 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 87b0a515d7a5..3dde9076d9d7 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -121,6 +121,22 @@ intel_dp_max_link_bw(struct intel_dp *intel_dp)
>>  	return max_link_bw;
>>  }
>>  
>> +static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
>> +{
>> +	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
>> +	struct drm_device *dev = intel_dig_port->base.base.dev;
>> +	u8 source_max, sink_max;
>> +
>> +	source_max = 4;
>> +	if (HAS_DDI(dev) && intel_dig_port->port == PORT_A &&
>> +	    (intel_dig_port->saved_port_bits & DDI_A_4_LANES) == 0)
>> +		source_max = 2;
>> +
>> +	sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
>> +
>> +	return min(source_max, sink_max);
>> +}
>> +
>>  /*
>>   * The units on the numbers in the next two are... bizarre.  Examples will
>>   * make it clearer; this one parallels an example in the eDP spec.
>> @@ -171,7 +187,7 @@ intel_dp_mode_valid(struct drm_connector *connector,
>>  	}
>>  
>>  	max_link_clock = drm_dp_bw_code_to_link_rate(intel_dp_max_link_bw(intel_dp));
>> -	max_lanes = drm_dp_max_lane_count(intel_dp->dpcd);
>> +	max_lanes = intel_dp_max_lane_count(intel_dp);
>>  
>>  	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
>>  	mode_rate = intel_dp_link_required(target_clock, 18);
>> @@ -769,7 +785,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>>  	struct intel_crtc *intel_crtc = encoder->new_crtc;
>>  	struct intel_connector *intel_connector = intel_dp->attached_connector;
>>  	int lane_count, clock;
>> -	int max_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
>> +	int max_lane_count = intel_dp_max_lane_count(intel_dp);
>>  	/* Conveniently, the link BW constants become indices with a shift...*/
>>  	int max_clock = intel_dp_max_link_bw(intel_dp) >> 3;
>>  	int bpp, mode_rate;
>> -- 
>> 1.9.1
>> 
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-- 
Jani Nikula, Intel Open Source Technology Center