[Intel-gfx] [PATCH] drm/i915: Interlaced DP output doesn't work on VLV/CHV

[Rodrigo Vivi]

On Wed, Nov 29, 2017 at 06:08:47PM +0000, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Reject interlaced modes on VLV/CHV DP outputs. This simply does
> not work correctly in the hardware. We do get some output, but
> it's quite corrupted.
> 
> The available documentation fails to mention this fact. I
> contacted some hardware people who eventually managed to locate
> the relevant HSD for VLV, which was resolved by declaring
> interlaced DP output as not supported. The HSD was never cloned
> for CHV even though it inherited most of the hardware and
> thus has the same problems with interlaced DP output.
> 
> Cc: Dennis Vshivkov <awesome.walrus+bugzilla at gmail.com>
> Reported-by: Dennis Vshivkov <awesome.walrus+bugzilla at gmail.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103922
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

I'm afraid we won't be able to track that down...
I took a quick look on wa_database for vlv/chv to see if
something seemed related, but nothing ring a bell...

So, let's live without these modes.

Acked-by: Rodrigo Vivi <rodrigo.vivi at intel.com>


> ---
>  drivers/gpu/drm/i915/intel_dp.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 957735c0b4c6..61cde5cd04d3 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1677,6 +1677,10 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>  						conn_state->scaling_mode);
>  	}
>  
> +	if ((IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) &&
> +	    adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
> +		return false;
> +
>  	if (adjusted_mode->flags & DRM_MODE_FLAG_DBLCLK)
>  		return false;
>  
> @@ -6083,7 +6087,8 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
>  	drm_connector_init(dev, connector, &intel_dp_connector_funcs, type);
>  	drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);
>  
> -	connector->interlace_allowed = true;
> +	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
> +		connector->interlace_allowed = true;
>  	connector->doublescan_allowed = 0;
>  
>  	intel_dp_init_connector_port_info(intel_dig_port);
> -- 
> 2.13.6
> 
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