[Intel-gfx] [PATCH] drm/i915: Restrict usage of live status check

[Ville Syrjälä]

On Thu, Mar 17, 2016 at 09:35:30PM +0530, Sharma, Shashank wrote:
> Regards
> Shashank
> 
> On 3/17/2016 9:31 PM, Ville Syrjälä wrote:
> > On Thu, Mar 17, 2016 at 09:15:39PM +0530, Sharma, Shashank wrote:
> >> Regards
> >> Shashank
> >>
> >> On 3/17/2016 6:34 PM, Ville Syrjälä wrote:
> >>> On Thu, Mar 17, 2016 at 01:29:25PM +0530, Shashank Sharma wrote:
> >>>> This patch 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 is not reliable
> >>>> on some older devices. So limit the live_status check from VLV onwards.
> >>>>
> >>>> This fixes a regression introduced in:
> >>>> 	commit: 237ed86 "drm/i915: Check live status"
> >>>> 	Author: Sonika Jindal <sonika.jindal at intel.com>
> >>>> 	Date:   Tue Sep 15 09:44:20 2015 +0530
> >>>>
> >>>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> >>>> ---
> >>>>    drivers/gpu/drm/i915/intel_hdmi.c | 22 ++++++++++++++--------
> >>>>    1 file changed, 14 insertions(+), 8 deletions(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> >>>> index e2dab48..d24d18a 100644
> >>>> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> >>>> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> >>>> @@ -1397,7 +1397,8 @@ 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;
> >>>> +	struct drm_device *dev = connector->dev;
> >>>> +	bool live_status = true;
> >>>>    	unsigned int try;
> >>>>
> >>>>    	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
> >>>> @@ -1405,16 +1406,21 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
> >>>>
> >>>>    	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,
> >>>> +	/*
> >>>> +	* Live status check for HDMI detection is not very
> >>>> +	* reliable on older platforms. So insist the live
> >>>> +	* status check for EDID read from VLV onwards.
> >>>> +	*/
> >>>> +	if (INTEL_INFO(dev)->gen >= 7 && !IS_IVYBRIDGE(dev)) {
> >>>> +		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));
> >>>> +		}
> >>>> +		DRM_DEBUG_KMS("Live status %s\n", live_status ? "up" : "down");
> >>>>    	}
> >>>>
> >>>> -	if (!live_status)
> >>>> -		DRM_DEBUG_KMS("Live status not up!");
> >>>> -
> >>>
> >>> As I said before, I think this whole thing could be solved with a simple
> >>> two-liner here:
> >>>
> >>> +	if (...)
> >>> +		live_status = true;
> >>>
> >> Yes I remember, and I replied on that already that why we would like to
> >> keep the live status check. In fact I would be ok to remove this check
> >> if you can suggest some other way of making this work for other
> >> operating systems/sw platforms.
> >
> > My two liner would keep the check.
> >
> Sorry, I might have not understood you properly.
> Do you mean:
> 	if (INTEL_INFO(dev)->gen < 7 && IS_IVYBRIDGE(dev)) {
> 		live_status = true;
> 	} else {
> 		do the same looping for retry;
> 	}

No, I mean

{
	...
	do loop;

	if (!live_status)
		DRM_DEBUG_KMS("Live status not up!");

+	if (don't trust live status)
+		live_status = true;
	
	intel_hdmi_unset_edid();
	
	if (intel_hdmi_set_edid(live_status)) {
	...
}


> 
> >>>>    	intel_hdmi_unset_edid(connector);
> >>>>
> >>>>    	if (intel_hdmi_set_edid(connector, live_status)) {
> >>>> --
> >>>> 1.9.1
> >>>
> >

-- 
Ville Syrjälä
Intel OTC