Re: [PATCH v2] drm/i915: Restrict usage of live status check

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 10 Mar 2016, Shashank Sharma <shashank.sharma@intel.com> wrote:
> This patch does the following:
> - Restricts usage of live status check for HDMI detection.
>   While testing certain (monitor + cable) combinations with
>   various intel  platforms, it seems that live status register
>   doesn't work reliably on some older devices. So limit the
>   live_status check for HDMI detection, only for platforms
>   from gen7 onwards.
> - Cleans up the retry logic.
>   There is an extra 'if (try)' check, which can be avoided by
>   changing the logic slightly, keeping the delay as same(80ms)

The commit message needs a reference to the commit that broke things.

BR,
Jani.

>
> V2: Ville: Skipped live_status check for IVB
>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index e2dab48..b1e67de 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1397,24 +1397,32 @@ 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;
> +	struct drm_device *dev = dev_priv->dev;
> +	bool live_status = true;
> +	unsigned int try = 9;
>  
>  	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);
> +	/*
> +	 * When tested with specific set of monitors + cables,
> +	 * live status behavior is not very consistent for older
> +	 * platforms. So add live status check from VLV
> +	 * onwards.
> +	 */
> +	if (INTEL_INFO(dev)->gen >= 7 && !IS_IVYBRIDGE(dev)) {
> +retry_ls:
>  		live_status = intel_digital_port_connected(dev_priv,
>  				hdmi_to_dig_port(intel_hdmi));
> +		if (!live_status && --try) {
> +			msleep(10);
> +			goto retry_ls;
> +		}
> +		DRM_DEBUG_KMS("Live status %s!\n", live_status ? "up" : "down");
>  	}
>  
> -	if (!live_status)
> -		DRM_DEBUG_KMS("Live status not up!");
> -
>  	intel_hdmi_unset_edid(connector);
>  
>  	if (intel_hdmi_set_edid(connector, live_status)) {

-- 
Jani Nikula, Intel Open Source Technology Center
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