Hello Laurent Thank you for your review. > -----Original Message----- > From: Laurent Pinchart [mailto:laurent.pinchart@xxxxxxxxxxxxxxxx] > Sent: Dienstag, 3. April 2018 20:53 > To: Ucan, Emre (ADITG/ESB) > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH] drm: rcar-du: track dma-buf fences > > Hello Emre, > > Thank you for the patch. > > On Tuesday, 3 April 2018 12:14:33 EEST Emre Ucan wrote: > > We have to check dma-buf reservation objects > > of our framebuffers before we use them. > > Otherwise, another driver might be writing > > on the same buffer which we are using. > > This would cause visible tearing effects > > on display. > > > > We can use existing atomic helper functions > > to solve this problem. > > > > Signed-off-by: Emre Ucan <eucan@xxxxxxxxxxxxxx> > > --- > > drivers/gpu/drm/rcar-du/rcar_du_kms.c | 2 ++ > > drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 20 ++++++++++++++++++++ > > 2 files changed, 22 insertions(+) > > > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c > > b/drivers/gpu/drm/rcar-du/rcar_du_kms.c index 0329b35..f3da3d1 100644 > > --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c > > @@ -255,6 +255,8 @@ static void rcar_du_atomic_commit_tail(struct > > drm_atomic_state *old_state) { > > struct drm_device *dev = old_state->dev; > > > > + drm_atomic_helper_wait_for_fences(dev, old_state, false); > > + > > The commit_tail() function in drm_atomic_helper.c, which calls our > atomic_commit_tail() implementation, already calls > drm_atomic_helper_wait_for_fences(). Why is there a need to duplicate the > call > here ? You are right. I will remove it in second version. > > > /* Apply the atomic update. */ > > drm_atomic_helper_commit_modeset_disables(dev, old_state); > > drm_atomic_helper_commit_planes(dev, old_state, > > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > > b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index 2c260c3..482e23c 100644 > > --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > > +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c > > @@ -18,12 +18,16 @@ > > #include <drm/drm_fb_cma_helper.h> > > #include <drm/drm_gem_cma_helper.h> > > #include <drm/drm_plane_helper.h> > > +#include <drm/drm_atomic.h> > > > > #include <linux/bitops.h> > > #include <linux/dma-mapping.h> > > +#include <linux/dma-fence.h> > > +#include <linux/dma-buf.h> > > #include <linux/of_platform.h> > > #include <linux/scatterlist.h> > > #include <linux/videodev2.h> > > +#include <linux/reservation.h> > > > > #include <media/vsp1.h> > > > > @@ -203,6 +207,20 @@ static void rcar_du_vsp_plane_setup(struct > > rcar_du_vsp_plane *plane) plane->index, &cfg); > > } > > > > +static void rcar_du_vsp_set_fence_for_plane(struct drm_plane_state > *state) > > +{ > > + struct drm_gem_cma_object *gem; > > + struct dma_buf *dma_buf; > > + struct dma_fence *fence; > > + > > + gem = drm_fb_cma_get_gem_obj(state->fb, 0); > > + dma_buf = gem->base.dma_buf; > > + if (dma_buf) { > > + fence = reservation_object_get_excl_rcu(dma_buf->resv); > > + drm_atomic_set_fence_for_plane(state, fence); > > Unless I'm mistaken this is used for implicit fencing only. What is your use > case, wouldn't it be better for userspace to use explicit fencing as that is > the fence model that has been selected for display ? We are using Weston on Renesas R-Car H3 SoC. I am using GPU rendered client buffers directly as scanout buffer for the display. Weston is not using explicit fencing. > > > + } > > +} > > This looks very similar to drm_gem_fb_prepare_fb(), couldn't you use that > function instead ? Description of drm_gem_fb_prepare_fb() function states that it can be used as the &drm_plane_helper_funcs.prepare_fb hook. But we have our own hook function which is called rcar_du_vsp_plane_prepare_fb(). Therefore, I was not sure if it is correct to use drm_gem_fb_prepare_fb() inside our hook function. I will use it in the second version nevertheless. > > > static int rcar_du_vsp_plane_prepare_fb(struct drm_plane *plane, > > struct drm_plane_state *state) > > { > > @@ -237,6 +255,8 @@ static int rcar_du_vsp_plane_prepare_fb(struct > drm_plane > > *plane, } > > } > > > > + rcar_du_vsp_set_fence_for_plane(state); > > + > > return 0; > > > > fail: > > -- > Regards, > > Laurent Pinchart > > Best Regards, Emre Ucan _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
