Re: [PATCH] drm/i915: add Type-C port to encoder name

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 29 Aug 2019, Simon Ser <simon.ser@intel.com> wrote:
> This patch adds the Type-C port number to the encoder name. This is an
> alternative to [1].
>
> [1]: https://patchwork.freedesktop.org/series/65695/
>
> Signed-off-by: Simon Ser <simon.ser@intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 8eb2b3ec01ed..e543d44a7105 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -4278,6 +4278,8 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
>  	bool init_hdmi, init_dp, init_lspcon = false;
>  	enum pipe pipe;
>  	enum phy phy = intel_port_to_phy(dev_priv, port);
> +	enum tc_port tc_port;
> +	char tc_suffix[128];

Please let's try to avoid arbitrary large-ish buffers on stack in the
kernel.

>  
>  	init_hdmi = port_info->supports_dvi || port_info->supports_hdmi;
>  	init_dp = port_info->supports_dp;
> @@ -4307,8 +4309,15 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
>  	intel_encoder = &intel_dig_port->base;
>  	encoder = &intel_encoder->base;
>  
> +	tc_port = intel_port_to_tc(dev_priv, port);
> +	if (tc_port != PORT_TC_NONE)
> +		snprintf(tc_suffix, sizeof(tc_suffix), "/TC#%d", tc_port + 1);
> +	else
> +		tc_suffix[0] = '\0';

I think I'd add a

const char *tc_port_name(enum tc_port)

similar to transcoder_name(). The magic +1 goes away as well.

> +
>  	drm_encoder_init(&dev_priv->drm, encoder, &intel_ddi_funcs,
> -			 DRM_MODE_ENCODER_TMDS, "DDI %c", port_name(port));
> +			 DRM_MODE_ENCODER_TMDS, "DDI %c%s", port_name(port),
> +			 tc_suffix);

This will be a bit tedious, but straightforward:

"DDI %c%s%s", port_name(port), tc_port == PORT_TC_NONE ? "" : "/",
tc_port == PORT_TC_NONE ? "" : tc_port_name(tc_port)

The long-term idea would be to make port_name() handle all this
internally, but it seems like a fairly intrusive change, and AFAICT you
can't trivially have const strings for that.

BR,
Jani.

>  
>  	intel_encoder->hotplug = intel_ddi_hotplug;
>  	intel_encoder->compute_output_type = intel_ddi_compute_output_type;

-- 
Jani Nikula, Intel Open Source Graphics Center
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