[Intel-gfx] [PATCH 3/3] drm/i915: Mark FBC B gone if pipe B is gone

[Luca Coelho]

On Thu, 2022-09-22 at 11:29 +0300, Ville Syrjälä wrote:
> On Thu, Sep 22, 2022 at 11:18:55AM +0300, Luca Coelho wrote:
> > On Fri, 2022-09-16 at 19:52 +0300, Ville Syrjala wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > If pipe B is fused off we also shouldn't have FBC B.
> > > 
> > > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_device_info.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
> > > index 1434dc33cf49..fbefebc023f1 100644
> > > --- a/drivers/gpu/drm/i915/intel_device_info.c
> > > +++ b/drivers/gpu/drm/i915/intel_device_info.c
> > > @@ -394,6 +394,7 @@ void intel_device_info_runtime_init(struct drm_i915_private *dev_priv)
> > >  		if (dfsm & SKL_DFSM_PIPE_B_DISABLE) {
> > >  			runtime->pipe_mask &= ~BIT(PIPE_B);
> > >  			runtime->cpu_transcoder_mask &= ~BIT(TRANSCODER_B);
> > > +			runtime->fbc_mask &= ~BIT(INTEL_FBC_B);
> > >  		}
> > >  		if (dfsm & SKL_DFSM_PIPE_C_DISABLE) {
> > >  			runtime->pipe_mask &= ~BIT(PIPE_C);
> > 
> > I don't know (yet) what exactly this does, but it makes sense if you
> > think of consistency: we already do that for PIPE_A.
> 
> It's basically saying the entire pipe is fused off, so anything
> living inside that pipe should also be fused off.
> 
> > 
> > But what about PIPE_C and PIPE_D? Wouldn't it make sense to do the same
> > thing for them as well?
> 
> There is no FBC engine on those pipes (we don't even have
> the INTEL_FBC_C+ enum values defined), at least for now.
> 

Okay, but AFAICT INTEL_FBC_B was defined but not really used directly
anywhere.  So wouldn't it make sense to add this for pipes C and D as
well? Then, if you ever just need to check if the pipe supports FBC,
you could just check that bit, without making any other assumptions.

--
Cheers,
Luca.