Re: [PATCH v2 2/2] drm/i915: fix intel_prepare_ddi

[Damien Lespiau <damien.lespiau@intel.com>]

On Fri, Apr 17, 2015 at 07:31:22PM +0300, Imre Deak wrote:
> At the moment intel_prepare_ddi buffer will iterate through both MST and
> CRT encoders, which is incorrect. Neither of these encoder types have an
> embedding intel_digital_port object, so for these encoder types we will
> use random data when dereferencing the corresponding
> intel_digital_port->port field.
> 
> Introduced in
> commit b403745c84592b26a0713e6944c2b109f6df5c82
> Author: Damien Lespiau <damien.lespiau@intel.com>
> Date:   Mon Aug 4 22:01:33 2014 +0100
> 
>     drm/i915: Iterate through the initialized DDIs to prepare their buffers
> 
> v2:
> - fix getting at the port for MST encoders too
> - make sure that intel_prepare_ddi_buffers() gets called for port E too
>   (Paulo)
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>

Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>

-- 
Damien

> ---
>  drivers/gpu/drm/i915/i915_drv.h  |  5 -----
>  drivers/gpu/drm/i915/intel_ddi.c | 28 ++++++++++++++++++----------
>  2 files changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 40ef672..c461b56 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -251,11 +251,6 @@ enum hpd_pin {
>  			    &dev->mode_config.connector_list,	\
>  			    base.head)
>  
> -#define for_each_digital_port(dev, digital_port)		\
> -	list_for_each_entry(digital_port,			\
> -			    &dev->mode_config.encoder_list,	\
> -			    base.base.head)
> -
>  #define for_each_encoder_on_crtc(dev, __crtc, intel_encoder) \
>  	list_for_each_entry((intel_encoder), &(dev)->mode_config.encoder_list, base.head) \
>  		if ((intel_encoder)->base.crtc == (__crtc))
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 903d395..9c1e74a 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -256,12 +256,11 @@ intel_dig_port_supports_hdmi(const struct intel_digital_port *intel_dig_port)
>   * in either FDI or DP modes only, as HDMI connections will work with both
>   * of those
>   */
> -static void intel_prepare_ddi_buffers(struct drm_device *dev,
> -				      struct intel_digital_port *intel_dig_port)
> +static void intel_prepare_ddi_buffers(struct drm_device *dev, enum port port,
> +				      bool supports_hdmi)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	u32 reg;
> -	int port = intel_dig_port->port;
>  	int i, n_hdmi_entries, n_dp_entries, n_edp_entries, hdmi_default_entry,
>  	    size;
>  	int hdmi_level = dev_priv->vbt.ddi_port_info[port].hdmi_level_shift;
> @@ -272,7 +271,7 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev,
>  	const struct ddi_buf_trans *ddi_translations;
>  
>  	if (IS_BROXTON(dev)) {
> -		if (!intel_dig_port_supports_hdmi(intel_dig_port))
> +		if (!supports_hdmi)
>  			return;
>  
>  		/* Vswing programming for HDMI */
> @@ -360,7 +359,7 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev,
>  		reg += 4;
>  	}
>  
> -	if (!intel_dig_port_supports_hdmi(intel_dig_port))
> +	if (!supports_hdmi)
>  		return;
>  
>  	/* Choose a good default if VBT is badly populated */
> @@ -380,18 +379,27 @@ static void intel_prepare_ddi_buffers(struct drm_device *dev,
>   */
>  void intel_prepare_ddi(struct drm_device *dev)
>  {
> -	struct intel_digital_port *intel_dig_port;
> +	struct intel_encoder *intel_encoder;
>  	bool visited[I915_MAX_PORTS] = { 0, };
>  
>  	if (!HAS_DDI(dev))
>  		return;
>  
> -	for_each_digital_port(dev, intel_dig_port) {
> -		if (visited[intel_dig_port->port])
> +	for_each_intel_encoder(dev, intel_encoder) {
> +		struct intel_digital_port *intel_dig_port;
> +		enum port port;
> +		bool supports_hdmi;
> +
> +		ddi_get_encoder_port(intel_encoder, &intel_dig_port, &port);
> +
> +		if (visited[port])
>  			continue;
>  
> -		intel_prepare_ddi_buffers(dev, intel_dig_port);
> -		visited[intel_dig_port->port] = true;
> +		supports_hdmi = intel_dig_port &&
> +				intel_dig_port_supports_hdmi(intel_dig_port);
> +
> +		intel_prepare_ddi_buffers(dev, port, supports_hdmi);
> +		visited[port] = true;
>  	}
>  }
>  
> -- 
> 2.1.0
> 
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