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

[Daniel Vetter]

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>

This regression has been introduced in

commit 06ea66b6bb445043dc25a9626254d5c130093199
Author: Todd Previte <tprevite at gmail.com>
Date:   Mon Jan 20 10:19:39 2014 -0700

    drm/i915: Enable 5.4Ghz (HBR2) link rate for Displayport 1.2-capable devices

Cc: Todd Previte <tprevite at gmail.com>
Cc: stable at vger.kernel.org

Jani, can you please pick this one up?
-Daniel

> ---
>  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))
>  		training_pattern = DP_TRAINING_PATTERN_3;
>  
>  	/* channel equalization */
> -- 
> 1.9.3
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch