[Intel-xe] [PATCH] drm/xe/display: Append dma_buf fences to framebuffer fences

[Ville Syrjälä]

On Thu, Jun 15, 2023 at 11:10:55AM +0000, Shankar, Uma wrote:
> 
> 
> > -----Original Message-----
> > From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of José Roberto
> > de Souza
> > Sent: Wednesday, June 7, 2023 1:50 AM
> > To: intel-xe at lists.freedesktop.org
> > Subject: [Intel-xe] [PATCH] drm/xe/display: Append dma_buf fences to framebuffer
> > fences
> > 
> > This is required to comply with KMS page flip requirements, and it is the only way to
> > synchronize framebuffer scanouts in Xe KMD.
> > 
> > UMDs are expected to attach a syncobj that will be signaled at the end of the GPU
> > job that is rendering in the framebuffer.
> > This way, the compositor can send jobs to the GPU to render the framebuffer and
> > without having to wait for it to complete, queue the page flip in KMS.
> > 
> > This fixes display glitches.
> 
> Looks Good to me.
> Reviewed-by: Uma Shankar <uma.shankar at intel.com>
> 
> @Ville: Can you also check this once and confirm.

Needs an actual explanation why the current code doesn't work.

> 
> Regards,
> Uma Shankar
> 
> > Link: https://gitlab.freedesktop.org/mesa/mesa/-/issues/8923
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_atomic_plane.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > index b756561f08bd1..a3f30a319e4c0 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > @@ -32,6 +32,7 @@
> >   */
> > 
> >  #include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_gem_atomic_helper.h>
> >  #include <drm/drm_blend.h>
> >  #include <drm/drm_fourcc.h>
> > 
> > @@ -1120,10 +1121,20 @@ intel_prepare_plane_fb(struct drm_plane *_plane,
> > 
> >  	return ret;
> >  #else
> > +	int ret;
> > +
> >  	if (!intel_fb_obj(new_plane_state->hw.fb))
> >  		return 0;
> > 
> > -	return intel_plane_pin_fb(new_plane_state);
> > +	ret = intel_plane_pin_fb(new_plane_state);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = drm_gem_plane_helper_prepare_fb(_plane, _new_plane_state);
> > +	if (ret)
> > +		intel_plane_unpin_fb(new_plane_state);
> > +
> > +	return ret;
> >  #endif
> >  }
> > 
> > --
> > 2.41.0
> 

-- 
Ville Syrjälä
Intel