[Intel-gfx] [PATCH 3/4] drm/i915/lspcon: Remove DPCD compare based resume time workaround

[Sharma, Shashank]

Regards

Shashank


On 1/27/2017 3:09 PM, Imre Deak wrote:
> This effectively reverts
> commit 489375c866c111f16cea93b2467ebe59c9022cc7
> Author: Imre Deak <imre.deak at intel.com>
> Date:   Mon Oct 24 19:33:31 2016 +0300
>
>      drm/i915/lspcon: Add workaround for resuming in PCON mode
>
> The workaround was added without considering that HPD is low during
> the failed AUX transfers the WA fixed. Since the previous patch we
> wait for HPD to get asserted. My tests also show that this happens
> _after_ the DPCD reads start to return correct values. This
> suggests that we don't need this WA any more, let's try to remove
> it to reduce the clutter.
>
> Cc: Shashank Sharma <shashank.sharma at intel.com>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>   drivers/gpu/drm/i915/intel_drv.h    |  1 -
>   drivers/gpu/drm/i915/intel_lspcon.c | 17 ++---------------
>   2 files changed, 2 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index b9cde11..b2882ff 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -989,7 +989,6 @@ struct intel_dp {
>   struct intel_lspcon {
>   	bool active;
>   	enum drm_lspcon_mode mode;
> -	bool desc_valid;
>   };
>   
>   struct intel_digital_port {
> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
> index c300647..71cbe9c 100644
> --- a/drivers/gpu/drm/i915/intel_lspcon.c
> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
> @@ -162,21 +162,8 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>   	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
>   	unsigned long start = jiffies;
>   
> -	if (!lspcon->desc_valid)
> -		return;
> -
>   	while (1) {
> -		struct intel_dp_desc desc;
> -
> -		/*
> -		 * The w/a only applies in PCON mode and we don't expect any
> -		 * AUX errors.
> -		 */
> -		if (!__intel_dp_read_desc(intel_dp, &desc))
> -			return;
> -
> -		if (intel_digital_port_connected(dev_priv, dig_port) &&
> -		    !memcmp(&intel_dp->desc, &desc, sizeof(desc))) {
> +		if (intel_digital_port_connected(dev_priv, dig_port)) {
Again, does it matter, as in PCON mode live_status will be always true ?
- Shashank
>   			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
>   				      jiffies_to_msecs(jiffies - start));
>   			return;
> @@ -253,7 +240,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>   		return false;
>   	}
>   
> -	lspcon->desc_valid = intel_dp_read_desc(dp);
> +	intel_dp_read_desc(dp);
>   
>   	DRM_DEBUG_KMS("Success: LSPCON init\n");
>   	return true;