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

[Ville Syrjälä]

On Wed, Nov 29, 2017 at 03:07:03PM -0800, Rodrigo Vivi wrote:
> 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>

Thanks. Pushed to dinq.

> 
> 
> > ---
> >  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
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC