[Intel-gfx] [PATCH] drm/i915: don't try using training pattern 3 on pre-haswell

[Jani Nikula]

On Wed, 29 Oct 2014, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Wed, Oct 29, 2014 at 05:02:50PM +1000, Dave Airlie wrote:
>> From: Dave Airlie <airlied at redhat.com>
>> 
>> Ivybridge + 30" monitor prints a drm error on every modeset, since
>> IVB doesn't support DP3 we should even bother trying to use it.
>> 
>> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch> (on irc)
>> Signed-off-by: Dave Airlie <airlied at redhat.com>
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index f6a3fdd..87cfb92 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -3547,13 +3547,15 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
>>  void
>>  intel_dp_complete_link_train(struct intel_dp *intel_dp)
>>  {
>> +	struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
>> +	struct drm_device *dev = encoder->dev;
>>  	bool channel_eq = false;
>>  	int tries, cr_tries;
>>  	uint32_t DP = intel_dp->DP;
>>  	uint32_t training_pattern = DP_TRAINING_PATTERN_2;
>>  
>>  	/* Training Pattern 3 for HBR2 ot 1.2 devices that support it*/
>> -	if (intel_dp->link_bw == DP_LINK_BW_5_4 || intel_dp->use_tps3)
>> +	if ((intel_dp->link_bw == DP_LINK_BW_5_4 || intel_dp->use_tps3) && !HAS_DDI(dev))
>
> CHV has pattern 3.

Is "supports tps3" the same set of platforms as "supports 5.4 Gbps"? We
should abstract the check from intel_dp_max_link_bw.

Jani.


>
>>  		training_pattern = DP_TRAINING_PATTERN_3;
>>  
>>  	/* channel equalization */
>> -- 
>> 1.9.3
>> 
>> _______________________________________________
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>> Intel-gfx at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> -- 
> Ville Syrjälä
> Intel OTC
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-- 
Jani Nikula, Intel Open Source Technology Center