Re: [PATCH 1/2] drm/i915: Optimize the live status retry logic

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Mar 11, 2016 at 11:50:59PM +0530, Shashank Sharma wrote:
> There is an extra 'if (try)' check, which can be avoided by
> changing the logic slightly, keeping the delay as same(80ms)
> 
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 17 +++++++----------
>  1 file changed, 7 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index e2dab48..b523a2f 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1397,24 +1397,21 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
>  	enum drm_connector_status status;
>  	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
>  	struct drm_i915_private *dev_priv = to_i915(connector->dev);
> -	bool live_status = false;
> -	unsigned int try;
> +	bool live_status = true;
> +	unsigned int try = 8;
>  
>  	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
>  		      connector->base.id, connector->name);
>  
>  	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
> -
> -	for (try = 0; !live_status && try < 9; try++) {
> -		if (try)
> -			msleep(10);
> +	live_status = intel_digital_port_connected(dev_priv,
> +		hdmi_to_dig_port(intel_hdmi));
> +	while (!live_status && try--) {
> +		msleep(10);
>  		live_status = intel_digital_port_connected(dev_priv,
> -				hdmi_to_dig_port(intel_hdmi));
> +			hdmi_to_dig_port(intel_hdmi));
>  	}

I still don't see the point in "optimizing" this and making it harder
to figure out how many times it's doing its thing. It's calling msleep()
and doing i2c, so any performance considerations are clearly out the
window.

>  
> -	if (!live_status)
> -		DRM_DEBUG_KMS("Live status not up!");
> -
>  	intel_hdmi_unset_edid(connector);
>  
>  	if (intel_hdmi_set_edid(connector, live_status)) {
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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