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

[Sharma, Shashank]

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;
	}

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