Re: [Intel-gfx] [PATCH v2] drm/i915: WARN if a port should use VBT provided vswing tables

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

On Fri, 16 Sep 2022, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> We don't parse the VBT vswing/preemphassis tables at all currently.
> Let's WARN if a port wants to use them so we get a heads up that
> whether we really need to implement this stuff or not. My
> current stash contains no VBTs with this bit set.
>
> v2: Move to print_ddi_port() (Jani)
>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

LGTM.

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


> ---
>  drivers/gpu/drm/i915/display/intel_bios.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
> index 28bdb936cd1f..4c543e8205ca 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2676,6 +2676,14 @@ static void print_ddi_port(const struct intel_bios_encoder_data *devdata,
>  		drm_dbg_kms(&i915->drm,
>  			    "Port %c VBT DP max link rate: %d\n",
>  			    port_name(port), dp_max_link_rate);
> +
> +	/*
> +	 * FIXME need to implement support for VBT
> +	 * vswing/preemph tables should this ever trigger.
> +	 */
> +	drm_WARN(&i915->drm, child->use_vbt_vswing,
> +		 "Port %c asks to use VBT vswing/preemph tables\n",
> +		 port_name(port));
>  }
>  
>  static void parse_ddi_port(struct intel_bios_encoder_data *devdata)

-- 
Jani Nikula, Intel Open Source Graphics Center