Re: [Intel-gfx] [PATCH] drm/i915: Fix mistake in intel_modeset_all_pipes condition

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Wed, Aug 09, 2023 at 11:38:08AM +0300, Jani Nikula wrote:
> On Wed, 09 Aug 2023, Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> wrote:
> > It is supposed to be "!intel_crtc_needs_modeset" - otherwise,
> > we are active exactly vice versa for active pipes: skipping if modeset
> > is needed and not skipping if not needed.
> 
> If the crtc *already* needs a full modeset, there's no need to force a
> modeset on it.
> 
> BR,
> Jani.

We have curently some issue with that. There are multiple places from where
intel_modeset_all_pipes is called. One is that when we do detect that mbus join
state had changed. All the previous checks indicated that fastset is enough,
however once we detect mbus join state had changed in skl_watermarks.c we call
this function there as well and I think it might act in a wrong way then.

So basically this condition checks whether we need to force a modeset, but not
if we need it, so no crtc's are supposed to escape this?
Could be then that we just calling that whole function there wrongly.

Stan

> 
> >
> > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > index 763ab569d8f32..4b1d7034078ca 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > @@ -5439,7 +5439,7 @@ int intel_modeset_all_pipes(struct intel_atomic_state *state,
> >  			return PTR_ERR(crtc_state);
> >  
> >  		if (!crtc_state->hw.active ||
> > -		    intel_crtc_needs_modeset(crtc_state))
> > +		    !intel_crtc_needs_modeset(crtc_state))
> >  			continue;
> >  
> >  		drm_dbg_kms(&dev_priv->drm, "[CRTC:%d:%s] Full modeset due to %s\n",
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center