[Intel-gfx] [PATCH 1/2] drm/i915/dp: Do not set master_trans bit in bitmak if INVALID_TRANSCODER

[Ville Syrjälä]

On Thu, Jan 23, 2020 at 06:25:29PM +0000, Souza, Jose wrote:
> On Wed, 2020-01-22 at 16:24 -0800, Manasi Navare wrote:
> > In the port sync mode, for the master crtc, the master_transcoder is
> > INVALID.
> > In that case since its value is -1, do not set the bit in the
> > bitmask.
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Fixes: d0eed1545fe7 ("drm/i915: Fix post-fastset modeset check for
> > port sync")
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> > b/drivers/gpu/drm/i915/display/intel_display.c
> > index 878d331b9e8c..79f9054078ea 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -14649,8 +14649,10 @@ static int intel_atomic_check(struct
> > drm_device *dev,
> >  		}
> >  
> >  		if (is_trans_port_sync_mode(new_crtc_state)) {
> > -			u8 trans = new_crtc_state-
> > >sync_mode_slaves_mask |
> > -				   BIT(new_crtc_state-
> > >master_transcoder);
> > +			u8 trans = new_crtc_state-
> > >sync_mode_slaves_mask;
> > +
> > +			if (new_crtc_state->master_transcoder !=
> > INVALID_TRANSCODER)
> > +				trans |= BIT(new_crtc_state-
> > >master_transcoder);
> 
> Why not set master_transcoder in port sync master too? Would avoid have
> this check here and in future other places.

Not how the hardware works. So would complicate hw readout and
programming code needlessly.

> 
> >  
> >  			if (intel_cpu_transcoders_need_modeset(state,
> > trans)) {
> >  				new_crtc_state->uapi.mode_changed =
> > true;

-- 
Ville Syrjälä
Intel