[Intel-gfx] [PATCH] drm/i915: Correct max delay for HDMI hotplug live status checking

[Daniel Vetter]

On Fri, Dec 11, 2015 at 03:12:05PM +0800, Gary Wang wrote:
> The total delay of HDMI hotplug detecting with 30ms should have
> been split into a resolution of 3 retries of 10ms each, for the worst
> cases. But it still suffered from only waiting 10ms at most in
> intel_hdmi_detect(). This patch corrects it by reading hotplug status
> with 4 times at most for 30ms delay.
> 
> Reviewed-by: Cooper Chiou <cooper.chiou at intel.com>
> Tested-by: Gary Wang <gary.c.wang at intel.com>
> Cc: Gavin Hindman <gavin.hindman at intel.com>
> Cc: Sonika Jindal <sonika.jindal at intel.com>
> Signed-off-by: Gary Wang <gary.c.wang at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>  mode change 100644 => 100755 drivers/gpu/drm/i915/intel_hdmi.c
> 
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> old mode 100644
> new mode 100755
> index be7fab9..ba042cf
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1394,11 +1394,13 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
>  
>  	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
>  
> -	while (!live_status && --retry) {
> +	do {
>  		live_status = intel_digital_port_connected(dev_priv,
>  				hdmi_to_dig_port(intel_hdmi));
> +		if (live_status || !retry)
> +			break;
>  		mdelay(10);
> -	}
> +	} while (retry--);

I agree with Ville, let's just go with an obviously correct for loop here.
This is apparently too hard ;-)
-Daniel

>  
>  	if (!live_status)
>  		DRM_DEBUG_KMS("Live status not up!");
> -- 
> 1.9.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch