Re: [PATCH 09/24] drm/i915: Keep vblank interrupts enabled while enabling/disabling planes

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Apr 07, 2014 at 06:21:08PM -0300, Paulo Zanoni wrote:
> 2014-03-07 13:32 GMT-03:00  <ville.syrjala@linux.intel.com>:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > We may have use for vblank interrupts during plane enabling/disabling, so
> > don't call drm_vblank_off() until planes are off, and call
> > drm_vblank_on() just before we start to enable the planes.
> 
> Just like the previous patch, this one also needs a more precise
> description of the reasons and consequences. If this is going to be
> needed in the future, it is probably a good idea to briefly describe
> why and the use case you are planning. Because if, in the future, we
> ever bisect a bug to this patch, and need to revert, we won't know if
> the revert breaks some other feature.

Yeah I guess I should s/may/will/ and say that it's required for
watermark updates.

> 
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_display.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 4986887..c028b5c 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -3545,6 +3545,8 @@ static void ilk_crtc_enable_planes(struct drm_crtc *crtc)
> >         int pipe = intel_crtc->pipe;
> >         int plane = intel_crtc->plane;
> >
> > +       drm_vblank_on(dev, pipe);
> > +
> >         intel_enable_primary_plane(dev_priv, plane, pipe);
> >         intel_enable_planes(crtc);
> >         intel_crtc_update_cursor(crtc, true);
> > @@ -3555,8 +3557,6 @@ static void ilk_crtc_enable_planes(struct drm_crtc *crtc)
> >         mutex_lock(&dev->struct_mutex);
> >         intel_update_fbc(dev);
> >         mutex_unlock(&dev->struct_mutex);
> > -
> > -       drm_vblank_on(dev, pipe);
> >  }
> >
> >  static void ilk_crtc_disable_planes(struct drm_crtc *crtc)
> > @@ -3568,7 +3568,6 @@ static void ilk_crtc_disable_planes(struct drm_crtc *crtc)
> >         int plane = intel_crtc->plane;
> >
> >         intel_crtc_wait_for_pending_flips(crtc);
> > -       drm_vblank_off(dev, pipe);
> >
> >         if (dev_priv->fbc.plane == plane)
> >                 intel_disable_fbc(dev);
> > @@ -3579,6 +3578,8 @@ static void ilk_crtc_disable_planes(struct drm_crtc *crtc)
> >         intel_disable_planes(crtc);
> >         intel_disable_primary_plane(dev_priv, plane, pipe);
> >         intel_wait_for_vblank(dev, pipe);
> > +
> > +       drm_vblank_off(dev, pipe);
> >  }
> >
> >  static void ironlake_crtc_enable(struct drm_crtc *crtc)
> > --
> > 1.8.3.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Paulo Zanoni

-- 
Ville Syrjälä
Intel OTC