[Intel-gfx] [PATCH] drm/i915: Allow panel drrs modes to have differing sync polarities

[Jani Nikula]

On Tue, 11 Jul 2023, Jani Nikula <jani.nikula at intel.com> wrote:
> On Tue, 11 Jul 2023, Vidya Srinivas <vidya.srinivas at intel.com> wrote:
>> v2: Add Jani Nikula's change for quirk for sync polarity
>
> This was a quick hack suggestion to try. If it works, I think it works
> by concidence, because a fastset won't update the sync flags in
> TRANS_DDI_FUNC_CTL register. Did not check whether they can even be
> updated while the transcoder is enabled.

Bspec 49198 seems to indicate TRANS_DDI_FUNC_CTL can be changed without
a full mode set.

The sync polarity still needs to be modified in the ->update_pipe()
hooks.


BR,
Jani.


>
>> CC: Jani Nikula <jani.nikula at intel.com>
>> Credits-to: Jani Nikula <jani.nikula at intel.com>
>> Signed-off-by: Vidya Srinivas <vidya.srinivas at intel.com>
>
> It would be useful to have a bug report at fdo gitlab with the EDID
> attached.
>
> BR,
> Jani.
>
>
>> ---
>>  drivers/gpu/drm/i915/display/intel_display.c |  2 +-
>>  drivers/gpu/drm/i915/display/intel_panel.c   | 10 ++++++----
>>  2 files changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>> index 43cba98f7753..088b45e032aa 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -5234,7 +5234,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>>  	PIPE_CONF_CHECK_FLAGS(hw.adjusted_mode.flags,
>>  			      DRM_MODE_FLAG_INTERLACE);
>>  
>> -	if (!PIPE_CONF_QUIRK(PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS)) {
>> +	if (!PIPE_CONF_QUIRK(PIPE_CONFIG_QUIRK_MODE_SYNC_FLAGS) && !fastset) {
>>  		PIPE_CONF_CHECK_FLAGS(hw.adjusted_mode.flags,
>>  				      DRM_MODE_FLAG_PHSYNC);
>>  		PIPE_CONF_CHECK_FLAGS(hw.adjusted_mode.flags,
>> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
>> index 9232a305b1e6..b9eeaedabd22 100644
>> --- a/drivers/gpu/drm/i915/display/intel_panel.c
>> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
>> @@ -112,10 +112,12 @@ intel_panel_fixed_mode(struct intel_connector *connector,
>>  static bool is_alt_drrs_mode(const struct drm_display_mode *mode,
>>  			     const struct drm_display_mode *preferred_mode)
>>  {
>> -	return drm_mode_match(mode, preferred_mode,
>> -			      DRM_MODE_MATCH_TIMINGS |
>> -			      DRM_MODE_MATCH_FLAGS |
>> -			      DRM_MODE_MATCH_3D_FLAGS) &&
>> +	u32 sync_flags = DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NHSYNC |
>> +		DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC;
>> +
>> +	return (mode->flags & ~sync_flags) == (preferred_mode->flags & ~sync_flags) &&
>> +		mode->hdisplay == preferred_mode->hdisplay &&
>> +		mode->vdisplay == preferred_mode->vdisplay &&
>>  		mode->clock != preferred_mode->clock;
>>  }

-- 
Jani Nikula, Intel Open Source Graphics Center