Re: [Intel-gfx] [PATCH 3/6] drm/i915/bios: Use i915->vbt.ports[] for all g4x+

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

On Fri, 17 Dec 2021, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Extend the vbt.ports[] stuff for all g4x+ platforms. We do need
> to drop the version check as some elk/ctg machines may have VBTs
> older than that. The oldest I know is an elk with version 142.
> But the child device stuff has had the correct size since at
> least version 125 (observed on my sdg), we from that angle this
> should be totally safe.
>
> This does couple of things:
> - Start using the aux_ch/ddc_pin from VBT instead of just the
>   hardcoded defaults. Hopefully there are no VBTs with entirely
>   bogus information here.
> - Start using i915->vbt.ports[] for intel_bios_is_port_dp_dual_mode().
>   Should be fine as the logic doesn't actually change.
> - Start using i915->vbt.ports[] for intel_bios_is_port_edp().
>   The old codepath only looks at the DP DVO ports, the new codepath
>   looks at both DP and HDMI DVO ports. In principle that should not
>   matter. We also stop looking at some of the other device type bits
>   (eg. LVDS,MIPI,ANALOG,etc.). Hopefully no VBT is broken enough that
>   it sets up totally conflicting device type bits (eg. LVDS+eDP at the
>   same time). We also lose the "g4x->no eDP ever" hardcoding (shouldn't
>   be hard to re-introduce that into eg. sanitize_device_type() if needed).

Aligns with what I figured in my reply earlier in the thread. I still
think we should do this for maintainability, even though there's a risk
we'll need to follow-up with additional checks/sanitization for older
platforms in parse_ddi_port().

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

>
> TODO: actually smoke test on various platforms
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_bios.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index b7adea9827c3..d7d64d3bf083 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2075,7 +2075,7 @@ static void parse_ddi_port(struct drm_i915_private *i915,
>  
>  static bool has_ddi_port_info(struct drm_i915_private *i915)
>  {
> -	return HAS_DDI(i915) || IS_CHERRYVIEW(i915);
> +	return DISPLAY_VER(i915) >= 5 || IS_G4X(i915);
>  }
>  
>  static void parse_ddi_ports(struct drm_i915_private *i915)
> @@ -2085,9 +2085,6 @@ static void parse_ddi_ports(struct drm_i915_private *i915)
>  	if (!has_ddi_port_info(i915))
>  		return;
>  
> -	if (i915->vbt.version < 155)
> -		return;
> -
>  	list_for_each_entry(devdata, &i915->vbt.display_devices, node)
>  		parse_ddi_port(i915, devdata);
>  }

-- 
Jani Nikula, Intel Open Source Graphics Center