ACK: [PATCH][Quantal] UBUNTU: SAUCE: i915_hsw: don't send DP "idle" pattern before "normal" on HSW PORT_A

[Stefan Bader]

On 06.03.2013 01:46, James M Leddy wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> To the OEMs, IHVs, and eventually end users, this message is
> scary. The reason is because this is written every time a laptop
> resumes, so if the driver fails for some other reason, then this is
> the only message you see.
> 
> Buglink: https://bugs.launchpad.net/bugs/1138700
> 
> cherry-picked-from: 10aa17c86f0de1fd902f7b8ee487a3682d7401df
> 
> Original commit message follows:
> 
> The DP_TP_STATUS register for PORT_A doesn't exist. Our documentation
> will be fixed soon, so the code does not match it for now.
> 
> This solves "Timed out waiting for DP idle patterns" and "unclaimed
> register" messages on eDP.
> 
> V1: Was called "drm/i915: don't read DP_TP_STATUS(PORT_A)"
> V2: Was called "drm/i915: don't send DP idle pattern before normal
> pattern on HSW"
> V3: Only change the code that touches PORT_A.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: James M Leddy <james.leddy at canonical.com>
> ---
>  ubuntu/i915/intel_dp.c |   16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/ubuntu/i915/intel_dp.c b/ubuntu/i915/intel_dp.c
> index 295d21e..f46d47b 100644
> --- a/ubuntu/i915/intel_dp.c
> +++ b/ubuntu/i915/intel_dp.c
> @@ -1697,14 +1697,18 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
>  		temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
>  		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
>  		case DP_TRAINING_PATTERN_DISABLE:
> -			temp |= DP_TP_CTL_LINK_TRAIN_IDLE;
> -			I915_WRITE(DP_TP_CTL(port), temp);
>  
> -			if (wait_for((I915_READ(DP_TP_STATUS(port)) &
> -				      DP_TP_STATUS_IDLE_DONE), 1))
> -				DRM_ERROR("Timed out waiting for DP idle patterns\n");
> +			if (port != PORT_A) {
> +				temp |= DP_TP_CTL_LINK_TRAIN_IDLE;
> +				I915_WRITE(DP_TP_CTL(port), temp);
> +
> +				if (wait_for((I915_READ(DP_TP_STATUS(port)) &
> +					      DP_TP_STATUS_IDLE_DONE), 1))
> +					DRM_ERROR("Timed out waiting for DP idle patterns\n");
> +
> +				temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
> +			}
>  
> -			temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
>  			temp |= DP_TP_CTL_LINK_TRAIN_NORMAL;
>  
>  			break;
> 
Simple cherry pick, seems to be doing what it claims.

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