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

[Souza, Jose]

On Tue, 2020-02-11 at 18:12 +0200, Jani Nikula wrote:
> 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().

Indeed thanks for catching, will send the fixed version in a bit.

> 
> 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,