[Intel-gfx] [PATCH] drm/i915/dp: Fix the channel equalization failure condition during Link Training

[Ville Syrjälä]

On Thu, Aug 17, 2017 at 08:03:04PM -0700, Manasi Navare wrote:
> In the channel EQ retry loop, we break from the loop in case
> of failure to get link status or failure in clock recovery or
> failure to update link training. In these cases channel_eq_status
> is still false even though the retry loop has not reached max retries.
> So we need to consider this as a failure condition.

This just prints a debug message, and each break in the loop also
prints some kind of debug/error message. So to me this just seems to
make it harder to see why things failed because we now point the finger
at channel EQ even when the actual error was something else.

> 
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> Cc: Jim Bride <jim.bride at linux.intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp_link_training.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
> index 05907fa..3fef219 100644
> --- a/drivers/gpu/drm/i915/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
> @@ -294,9 +294,9 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
>  	}
>  
>  	/* Try 5 times, else fail and try at lower BW */
> -	if (tries == 5) {
> +	if (tries == 5 || !intel_dp->channel_eq_status) {
>  		intel_dp_dump_link_status(link_status);
> -		DRM_DEBUG_KMS("Channel equalization failed 5 times\n");
> +		DRM_DEBUG_KMS("Channel equalization failed\n");
>  	}
>  
>  	intel_dp_set_idle_link_train(intel_dp);
> -- 
> 2.1.4

-- 
Ville Syrjälä
Intel OTC