[PATCH v2] drm/i915: Fake HDMI live status

[PATCH v2] drm/i915: Fake HDMI live status

[Shashank Sharma]

This patch does the following:
- Fakes live status of HDMI as connected (even if that's not).
  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.

This fixes regression added by patch:
  'commit 237ed86c693d ("drm/i915: Check live status before reading edid")'

V2: restrict faking live_status to certain platforms

Based on suggestion by: Ville Syrjala<ville.syrjala@linux.intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
---
 drivers/gpu/drm/i915/intel_hdmi.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index b199ede..c2150db 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1412,8 +1412,16 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 				hdmi_to_dig_port(intel_hdmi));
 	}
 
-	if (!live_status)
-		DRM_DEBUG_KMS("Live status not up!");
+	/*
+	* Live status reg is not reliable for all older platforms
+	* So for certain platforms, dont block EDID read even if
+	* live_status is down, give EDID a shot.
+	*/
+	if ((INTEL_INFO(dev_priv)->gen < 7 || IS_IVYBRIDGE(dev_priv))
+		&& !live_status) {
+		DRM_DEBUG_KMS("Warning: live status not up, faking it\n");
+		live_status = true;
+	}
 
 	intel_hdmi_unset_edid(connector);
 
-- 
1.9.1

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Re: [PATCH v2] drm/i915: Fake HDMI live status

[Ville Syrjälä]

On Thu, Apr 21, 2016 at 10:21:59AM +0530, Shashank Sharma wrote:
> This patch does the following:
> - Fakes live status of HDMI as connected (even if that's not).
>   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.
> 
> This fixes regression added by patch:
>   'commit 237ed86c693d ("drm/i915: Check live status before reading edid")'
> 
> V2: restrict faking live_status to certain platforms
> 
> Based on suggestion by: Ville Syrjala<ville.syrjala@linux.intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>

Did we have any bugs open for this? Those should be listed here.

> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index b199ede..c2150db 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1412,8 +1412,16 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
>  				hdmi_to_dig_port(intel_hdmi));
>  	}
>  
> -	if (!live_status)
> -		DRM_DEBUG_KMS("Live status not up!");

I think we should keep this debug for the other platforms.

> +	/*
> +	* Live status reg is not reliable for all older platforms
> +	* So for certain platforms, dont block EDID read even if
> +	* live_status is down, give EDID a shot.
> +	*/

Comment is misindented.

> +	if ((INTEL_INFO(dev_priv)->gen < 7 || IS_IVYBRIDGE(dev_priv))
> +		&& !live_status) {

Indent fail here too.

> +		DRM_DEBUG_KMS("Warning: live status not up, faking it\n");

The "Warning: " prefix seems a bit pointless.

The rest looks good to me.

> +		live_status = true;
> +	}
>  
>  	intel_hdmi_unset_edid(connector);
>  
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel OTC
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Re: [PATCH v2] drm/i915: Fake HDMI live status

[Jani Nikula]

On Thu, 21 Apr 2016, Shashank Sharma <shashank.sharma@intel.com> wrote:
> This patch does the following:
> - Fakes live status of HDMI as connected (even if that's not).
>   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.
>
> This fixes regression added by patch:
>   'commit 237ed86c693d ("drm/i915: Check live status before reading edid")'

Fixes: 237ed86c693d ("drm/i915: Check live status before reading edid")
Cc: stable@vger.kernel.org # v4.4

>
> V2: restrict faking live_status to certain platforms
>
> Based on suggestion by: Ville Syrjala<ville.syrjala@linux.intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index b199ede..c2150db 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1412,8 +1412,16 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
>  				hdmi_to_dig_port(intel_hdmi));
>  	}
>  
> -	if (!live_status)
> -		DRM_DEBUG_KMS("Live status not up!");
> +	/*
> +	* Live status reg is not reliable for all older platforms
> +	* So for certain platforms, dont block EDID read even if
> +	* live_status is down, give EDID a shot.
> +	*/
> +	if ((INTEL_INFO(dev_priv)->gen < 7 || IS_IVYBRIDGE(dev_priv))
> +		&& !live_status) {
> +		DRM_DEBUG_KMS("Warning: live status not up, faking it\n");
> +		live_status = true;
> +	}
>  
>  	intel_hdmi_unset_edid(connector);

-- 
Jani Nikula, Intel Open Source Technology Center
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