On Wed, Feb 12, 2020 at 04:08:11PM +0200, Jyri Sarha wrote: > On 12/02/2020 15:59, Jyri Sarha wrote: > > The old implementation of placing planes on the CRTC while configuring > > the planes was naive and relied on the order in which the planes were > > configured, enabled, and disabled. The situation where a plane's zpos > > was changed on the fly was completely broken. The usual symptoms of > > this problem was scrambled display and a flood of sync lost errors, > > when a plane was active in two layers at the same time, or a missing > > plane, in case when a layer was accidentally disabled. > > > > The rewrite takes a more straight forward approach when HW is > > concerned. The plane positioning registers are in the CRTC (actually > > OVR) register space and it is more natural to configure them in one go > > while configuring the CRTC. To do this we need to make sure we have > > all the planes on updated CRTCs in the new atomic state to be > > committed. This is done by calling drm_atomic_add_affected_planes() in > > crtc_atomic_check(). > > > > Signed-off-by: Jyri Sarha <jsarha@xxxxxx> > > --- > > drivers/gpu/drm/tidss/tidss_crtc.c | 55 ++++++++++++++++++++++++++++- > > drivers/gpu/drm/tidss/tidss_dispc.c | 55 +++++++++++------------------ > > drivers/gpu/drm/tidss/tidss_dispc.h | 5 +++ > > 3 files changed, 79 insertions(+), 36 deletions(-) > > > > diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c > > index 032c31ee2820..f7c5fd1094a8 100644 > > --- a/drivers/gpu/drm/tidss/tidss_crtc.c > > +++ b/drivers/gpu/drm/tidss/tidss_crtc.c > ... > > @@ -108,7 +110,54 @@ static int tidss_crtc_atomic_check(struct drm_crtc *crtc, > > return -EINVAL; > > } > > > > - return dispc_vp_bus_check(dispc, hw_videoport, state); > > + ret = dispc_vp_bus_check(dispc, hw_videoport, state); > > + if (ret) > > + return ret; > > + > > + /* Add unchanged planes on this crtc to state for zpos update. */ > > + return drm_atomic_add_affected_planes(state->state, crtc); > > Is this a correct way to use drm_atomic_add_affected_planes()? > > I saw that some other drivers implement their own mode_config > atomic_check() and have this call there in > for_each_new_crtc_in_state()-loop, but I thought it should be fine to > call it in crtc_atomic_check(). You seem to be using drm_atomic_helper_check_planes(), which means crtc.atomic_check() gets called after plane.atomic_check(). So this might be good or bad depending on whether you'd like the planes you add here to go through their .atomic_check() or not. -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
