Re: [PATCH v2 6/7] drm/i915/bios: use ddc pin directly from child data

["Nautiyal, Ankit K" <ankit.k.nautiyal@xxxxxxxxx>]

LGTM.

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>

On 9/1/2021 9:40 PM, Jani Nikula wrote:
> Avoid extra caching of the data. This is slightly more subtle than one
> would think. For one thing, we explicitly ignore 0 value in child device
> ddc pin; this is specified as N/A and does not warrant a warning. For
> another, we start looking for ddc pin collisions in sanitize using
> unmapped pin numbering.
>
> v2: Check !devdata in intel_bios_alternate_ddc_pin()
>
> Cc: José Roberto de Souza <jose.souza@xxxxxxxxx>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> ---
>   drivers/gpu/drm/i915/display/intel_bios.c | 49 +++++++++++++----------
>   drivers/gpu/drm/i915/i915_drv.h           |  2 -
>   2 files changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index b4113506b3b8..0c16a848a6e4 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -1589,28 +1589,43 @@ static enum port get_port_by_ddc_pin(struct drm_i915_private *i915, u8 ddc_pin)
>   	for_each_port(port) {
>   		info = &i915->vbt.ddi_port_info[port];
>   
> -		if (info->devdata && ddc_pin == info->alternate_ddc_pin)
> +		if (info->devdata && ddc_pin == info->devdata->child.ddc_pin)
>   			return port;
>   	}
>   
>   	return PORT_NONE;
>   }
>   
> -static void sanitize_ddc_pin(struct drm_i915_private *i915,
> +static void sanitize_ddc_pin(struct intel_bios_encoder_data *devdata,
>   			     enum port port)
>   {
> -	struct ddi_vbt_port_info *info = &i915->vbt.ddi_port_info[port];
> +	struct drm_i915_private *i915 = devdata->i915;
> +	struct ddi_vbt_port_info *info;
>   	struct child_device_config *child;
> +	u8 mapped_ddc_pin;
>   	enum port p;
>   
> -	p = get_port_by_ddc_pin(i915, info->alternate_ddc_pin);
> +	if (!devdata->child.ddc_pin)
> +		return;
> +
> +	mapped_ddc_pin = map_ddc_pin(i915, devdata->child.ddc_pin);
> +	if (!intel_gmbus_is_valid_pin(i915, mapped_ddc_pin)) {
> +		drm_dbg_kms(&i915->drm,
> +			    "Port %c has invalid DDC pin %d, "
> +			    "sticking to defaults\n",
> +			    port_name(port), mapped_ddc_pin);
> +		devdata->child.ddc_pin = 0;
> +		return;
> +	}
> +
> +	p = get_port_by_ddc_pin(i915, devdata->child.ddc_pin);
>   	if (p == PORT_NONE)
>   		return;
>   
>   	drm_dbg_kms(&i915->drm,
>   		    "port %c trying to use the same DDC pin (0x%x) as port %c, "
>   		    "disabling port %c DVI/HDMI support\n",
> -		    port_name(port), info->alternate_ddc_pin,
> +		    port_name(port), mapped_ddc_pin,
>   		    port_name(p), port_name(p));
>   
>   	/*
> @@ -1628,7 +1643,7 @@ static void sanitize_ddc_pin(struct drm_i915_private *i915,
>   	child->device_type &= ~DEVICE_TYPE_TMDS_DVI_SIGNALING;
>   	child->device_type |= DEVICE_TYPE_NOT_HDMI_OUTPUT;
>   
> -	info->alternate_ddc_pin = 0;
> +	child->ddc_pin = 0;
>   }
>   
>   static enum port get_port_by_aux_ch(struct drm_i915_private *i915, u8 aux_ch)
> @@ -1966,20 +1981,8 @@ static void parse_ddi_port(struct drm_i915_private *i915,
>   		    supports_typec_usb, supports_tbt,
>   		    devdata->dsc != NULL);
>   
> -	if (is_dvi) {
> -		u8 ddc_pin;
> -
> -		ddc_pin = map_ddc_pin(i915, child->ddc_pin);
> -		if (intel_gmbus_is_valid_pin(i915, ddc_pin)) {
> -			info->alternate_ddc_pin = ddc_pin;
> -			sanitize_ddc_pin(i915, port);
> -		} else {
> -			drm_dbg_kms(&i915->drm,
> -				    "Port %c has invalid DDC pin %d, "
> -				    "sticking to defaults\n",
> -				    port_name(port), ddc_pin);
> -		}
> -	}
> +	if (is_dvi)
> +		sanitize_ddc_pin(devdata, port);
>   
>   	if (is_dp)
>   		sanitize_aux_ch(devdata, port);
> @@ -2993,8 +2996,12 @@ int intel_bios_dp_max_link_rate(struct intel_encoder *encoder)
>   int intel_bios_alternate_ddc_pin(struct intel_encoder *encoder)
>   {
>   	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	const struct intel_bios_encoder_data *devdata = i915->vbt.ddi_port_info[encoder->port].devdata;
> +
> +	if (!devdata || !devdata->child.ddc_pin)
> +		return 0;
>   
> -	return i915->vbt.ddi_port_info[encoder->port].alternate_ddc_pin;
> +	return map_ddc_pin(i915, devdata->child.ddc_pin);
>   }
>   
>   bool intel_bios_encoder_supports_typec_usb(const struct intel_bios_encoder_data *devdata)
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 032d59119407..744181cbe21c 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -638,8 +638,6 @@ i915_fence_timeout(const struct drm_i915_private *i915)
>   struct ddi_vbt_port_info {
>   	/* Non-NULL if port present. */
>   	struct intel_bios_encoder_data *devdata;
> -
> -	u8 alternate_ddc_pin;
>   };
>   
>   enum psr_lines_to_wait {