[Intel-gfx] [PATCH] drm/i915/mst: Set intel_dp_set_m_n() for MST slaves

[Jani Nikula]

On Mon, 10 Feb 2020, Jani Nikula <jani.nikula at intel.com> wrote:
> On Mon, 10 Feb 2020, José Roberto de Souza <jose.souza at intel.com> wrote:
>> Commit 1c9d2eb24153 ("drm/i915: move intel_dp_set_m_n() to encoder for
>> DDI platforms") moved the intel_dp_set_m_n() from hsw_crtc_enable()
>> to intel_ddi_pre_enable_dp() but it missed add it to
>> intel_mst_pre_enable_dp() causing MST slaves to not work.
>>
>> Fixes: 1c9d2eb24153 ("drm/i915: move intel_dp_set_m_n() to encoder for DDI platforms")
>> Cc: Vandita Kulkarni <vandita.kulkarni at intel.com>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
>
> Damn it, this is the second DP MST thing I missed in the same
> series. *facepalm*. The first goof-up was fixed in commit 274959622017
> ("drm/i915/mst: fix pipe and vblank enable"). We really need more MST in
> CI.

Actually, wondering if the intel_dp_set_m_n() call in
intel_ddi_pre_enable_dp() now needs to be wrapped in

	if (!intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST))

Similar to intel_ddi_set_dp_msa().

BR,
Jani.


>
> Reviewed-by: Jani Nikula <jani.nikula at intel.com>
>
>> ---
>>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> index 9cd59141953d..d7bfa7c350e9 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> @@ -480,6 +480,8 @@ static void intel_mst_pre_enable_dp(struct intel_encoder *encoder,
>>  		intel_ddi_enable_pipe_clock(pipe_config);
>>  
>>  	intel_ddi_set_dp_msa(pipe_config, conn_state);
>> +
>> +	intel_dp_set_m_n(pipe_config, M1_N1);
>>  }
>>  
>>  static void intel_mst_enable_dp(struct intel_encoder *encoder,

-- 
Jani Nikula, Intel Open Source Graphics Center