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

[Ville Syrjälä]

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.

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

-- 
Ville Syrjälä
Intel OTC