[PATCH] drm/i915/hdmi: enable resolution 3840x2160 for type 1 HDMI

[PATCH] drm/i915/hdmi: enable resolution 3840x2160 for type 1 HDMI

[Jian-Hong Pan]

Type 1 HDMI may be version 1.3 or upper, which supports higher max TMDS
clock for higher resolutions, like 3840x2160. This patch sets max TMDS
clock according to the chip, if the adapter is type 1 HDMI.

Buglink: https://bugs.freedesktop.org/show_bug.cgi?id=112018
Fixes: b1ba124d8e95 ("drm/i915: Respect DP++ adaptor TMDS clock limit")
Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
---
 drivers/gpu/drm/i915/display/intel_hdmi.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index e02f0faecf02..74e4426ffcad 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2454,6 +2454,7 @@ intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_hdmi *hdmi = intel_attached_hdmi(connector);
+	struct intel_encoder *encoder = &hdmi_to_dig_port(hdmi)->base;
 	enum port port = hdmi_to_dig_port(hdmi)->base.port;
 	struct i2c_adapter *adapter =
 		intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
@@ -2488,8 +2489,16 @@ intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
 		return;
 
 	hdmi->dp_dual_mode.type = type;
-	hdmi->dp_dual_mode.max_tmds_clock =
-		drm_dp_dual_mode_max_tmds_clock(type, adapter);
+	/* Type 1 HDMI may be version 1.3 or upper, which supports higher max
+	 * TMDS clock for higher resolutions, like 3840x2160. So, set it
+	 * according to the chip, if the adapter is type 1 HDMI.
+	 */
+	if (type == DRM_DP_DUAL_MODE_TYPE1_HDMI)
+		hdmi->dp_dual_mode.max_tmds_clock =
+			intel_hdmi_source_max_tmds_clock(encoder);
+	else
+		hdmi->dp_dual_mode.max_tmds_clock =
+			drm_dp_dual_mode_max_tmds_clock(type, adapter);
 
 	DRM_DEBUG_KMS("DP dual mode adaptor (%s) detected (max TMDS clock: %d kHz)\n",
 		      drm_dp_get_dual_mode_type_name(type),
-- 
2.23.0

Re: [PATCH] drm/i915/hdmi: enable resolution 3840x2160 for type 1 HDMI

[Ville Syrjälä]

On Wed, Oct 16, 2019 at 05:57:58PM +0800, Jian-Hong Pan wrote:
> Type 1 HDMI may be version 1.3 or upper, which supports higher max TMDS
> clock for higher resolutions,

Spec says "Type 1 adaptors can support DVI or HDMI up to a 165MHz TMDS clock rate."

And I've definitely seen HDMI dongles that can't deal with
eg. 1080p 12bpc @225MHz. We don't want users with black screens
out of the box, so NAK.

If you want to "overclock" your hardware you can do so by setting up
the modeline manually.

> like 3840x2160. This patch sets max TMDS
> clock according to the chip, if the adapter is type 1 HDMI.
> 
> Buglink: https://bugs.freedesktop.org/show_bug.cgi?id=112018
> Fixes: b1ba124d8e95 ("drm/i915: Respect DP++ adaptor TMDS clock limit")
> Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdmi.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index e02f0faecf02..74e4426ffcad 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -2454,6 +2454,7 @@ intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(connector->dev);
>  	struct intel_hdmi *hdmi = intel_attached_hdmi(connector);
> +	struct intel_encoder *encoder = &hdmi_to_dig_port(hdmi)->base;
>  	enum port port = hdmi_to_dig_port(hdmi)->base.port;
>  	struct i2c_adapter *adapter =
>  		intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
> @@ -2488,8 +2489,16 @@ intel_hdmi_dp_dual_mode_detect(struct drm_connector *connector, bool has_edid)
>  		return;
>  
>  	hdmi->dp_dual_mode.type = type;
> -	hdmi->dp_dual_mode.max_tmds_clock =
> -		drm_dp_dual_mode_max_tmds_clock(type, adapter);
> +	/* Type 1 HDMI may be version 1.3 or upper, which supports higher max
> +	 * TMDS clock for higher resolutions, like 3840x2160. So, set it
> +	 * according to the chip, if the adapter is type 1 HDMI.
> +	 */
> +	if (type == DRM_DP_DUAL_MODE_TYPE1_HDMI)
> +		hdmi->dp_dual_mode.max_tmds_clock =
> +			intel_hdmi_source_max_tmds_clock(encoder);
> +	else
> +		hdmi->dp_dual_mode.max_tmds_clock =
> +			drm_dp_dual_mode_max_tmds_clock(type, adapter);
>  
>  	DRM_DEBUG_KMS("DP dual mode adaptor (%s) detected (max TMDS clock: %d kHz)\n",
>  		      drm_dp_get_dual_mode_type_name(type),
> -- 
> 2.23.0

-- 
Ville Syrjälä
Intel