Re: [Intel-gfx] [PATCH] drm/i915/display : Remove support for interlace mode

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

On Wed, 14 Jun 2023, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
> On Wed, Jun 14, 2023 at 09:37:49AM +0530, Ankit Nautiyal wrote:
>> There are multiple panels with which Interlace mode is seen to cause
>> flickering (interlacing artifacts) with different platforms.
>> 
>> The issue is seen with both HDMI, DP with CML, CFL, ICL, EHL with
>> different display models from Acer, Benq, Dell etc.
>> There are some models where the issue is not seen with same setup.
>> 
>> Due to this, cases where multiple display are configured in clone mode,
>> sometimes interlaced mode gets picked up in one of the displays
>> and flickers are seen.
>> 
>> Since its difficult to pin point if issue is due to the HW or due to
>> panels, removing interlace mode for DP and HDMI till this is
>> root caused.
>
> I though people already confirmewd the problem on non-Intel hw?
> So seems pretty clear that it's the displays themselves that are
> garbage.

Moreover, later means never. If you brush it under the carpet, nobody's
ever going to root cause it.

BR,
Jani.


>
>> 
>> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8395
>> 
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_dp.c   | 3 ---
>>  drivers/gpu/drm/i915/display/intel_hdmi.c | 3 ---
>>  2 files changed, 6 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> index f4192fda1a76..78d8ceb590a3 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -5665,9 +5665,6 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
>>  	drm_connector_init(dev, connector, &intel_dp_connector_funcs, type);
>>  	drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);
>>  
>> -	if (!HAS_GMCH(dev_priv) && DISPLAY_VER(dev_priv) < 12)
>> -		connector->interlace_allowed = true;
>> -
>>  	intel_connector->polled = DRM_CONNECTOR_POLL_HPD;
>>  
>>  	intel_dp_aux_init(intel_dp);
>> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
>> index 7ac5e6c5e00d..9b3ea307ef40 100644
>> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
>> @@ -2998,9 +2998,6 @@ void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
>>  				    ddc);
>>  	drm_connector_helper_add(connector, &intel_hdmi_connector_helper_funcs);
>>  
>> -	if (DISPLAY_VER(dev_priv) < 12)
>> -		connector->interlace_allowed = true;
>> -
>>  	connector->stereo_allowed = true;
>>  
>>  	if (DISPLAY_VER(dev_priv) >= 10)
>> -- 
>> 2.40.1

-- 
Jani Nikula, Intel Open Source Graphics Center