On Thu, 15 Nov 2018 12:39:42 -0800
Eric Anholt <eric@xxxxxxxxxx> wrote:
> Boris Brezillon <boris.brezillon@xxxxxxxxxxx> writes:
>
> > We are about to use vc4_plane_mode_set() in the async check path, and
> > async updates require that LBM size stay the same since they reuse the
> > LBM from the previous state. So we definitely don't want to allocate a
> > new LBM region that we know for sure will be free right away.
> >
> > Move the LBM allocation out of vc4_plane_mode_set() and call the new
> > function (vc4_plane_update_lbm()) from vc4_plane_atomic_check().
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/vc4/vc4_drv.h | 1 +
> > drivers/gpu/drm/vc4/vc4_plane.c | 82 ++++++++++++++++++++++-----------
> > 2 files changed, 55 insertions(+), 28 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> > index bd6ef1f31822..9ed05fb61eb6 100644
> > --- a/drivers/gpu/drm/vc4/vc4_drv.h
> > +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> > @@ -338,6 +338,7 @@ struct vc4_plane_state {
> > u32 pos0_offset;
> > u32 pos2_offset;
> > u32 ptr0_offset;
> > + u32 lbm_offset;
> >
> > /* Offset where the plane's dlist was last stored in the
> > * hardware at vc4_crtc_atomic_flush() time.
> > diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
> > index f6e3e8d33115..392a51f2bf8f 100644
> > --- a/drivers/gpu/drm/vc4/vc4_plane.c
> > +++ b/drivers/gpu/drm/vc4/vc4_plane.c
> > @@ -452,6 +452,43 @@ static void vc4_write_scaling_parameters(struct drm_plane_state *state,
> > }
> > }
> >
> > +static int vc4_plane_update_lbm(struct drm_plane_state *state)
> > +{
> > + struct vc4_dev *vc4 = to_vc4_dev(state->plane->dev);
> > + struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
> > + unsigned long irqflags;
> > + u32 lbm_size;
> > +
> > + lbm_size = vc4_lbm_size(state);
> > + if (!lbm_size)
> > + return 0;
> > +
> > + if (WARN_ON(!vc4_state->lbm_offset))
> > + return -EINVAL;
> > +
> > + /* Allocate the LBM memory that the HVS will use for temporary
> > + * storage due to our scaling/format conversion.
> > + */
> > + if (!vc4_state->lbm.allocated) {
> > + int ret;
> > +
> > + spin_lock_irqsave(&vc4->hvs->mm_lock, irqflags);
> > + ret = drm_mm_insert_node_generic(&vc4->hvs->lbm_mm,
> > + &vc4_state->lbm,
> > + lbm_size, 32, 0, 0);
> > + spin_unlock_irqrestore(&vc4->hvs->mm_lock, irqflags);
> > +
> > + if (ret)
> > + return ret;
> > + } else {
> > + WARN_ON_ONCE(lbm_size != vc4_state->lbm.size);
> > + }
> > +
> > + vc4_state->dlist[vc4_state->lbm_offset] = vc4_state->lbm.start;
> > +
> > + return 0;
> > +}
> > +
> > /* Writes out a full display list for an active plane to the plane's
> > * private dlist state.
> > */
> > @@ -469,31 +506,12 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
> > bool mix_plane_alpha;
> > bool covers_screen;
> > u32 scl0, scl1, pitch0;
> > - u32 lbm_size, tiling;
> > - unsigned long irqflags;
> > + u32 tiling;
> > u32 hvs_format = format->hvs;
> > int ret, i;
> >
> > - ret = vc4_plane_setup_clipping_and_scaling(state);
> > - if (ret)
> > - return ret;
> > -
> > - /* Allocate the LBM memory that the HVS will use for temporary
> > - * storage due to our scaling/format conversion.
> > - */
> > - lbm_size = vc4_lbm_size(state);
> > - if (lbm_size) {
> > - if (!vc4_state->lbm.allocated) {
> > - spin_lock_irqsave(&vc4->hvs->mm_lock, irqflags);
> > - ret = drm_mm_insert_node_generic(&vc4->hvs->lbm_mm,
> > - &vc4_state->lbm,
> > - lbm_size, 32, 0, 0);
> > - spin_unlock_irqrestore(&vc4->hvs->mm_lock, irqflags);
> > - } else {
> > - WARN_ON_ONCE(lbm_size != vc4_state->lbm.size);
> > - }
> > - }
> >
> > + ret = vc4_plane_setup_clipping_and_scaling(state);
> > if (ret)
> > return ret;
> >
> > @@ -717,15 +735,18 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
> > vc4_dlist_write(vc4_state, SCALER_CSC2_ITR_R_601_5);
> > }
> >
> > + vc4_state->lbm_offset = 0;
> > +
> > if (vc4_state->x_scaling[0] != VC4_SCALING_NONE ||
> > vc4_state->x_scaling[1] != VC4_SCALING_NONE ||
> > vc4_state->y_scaling[0] != VC4_SCALING_NONE ||
> > vc4_state->y_scaling[1] != VC4_SCALING_NONE) {
> > - /* LBM Base Address. */
> > + /* Reserve a slot for the LBM Base Address. The real value will
> > + * be set when calling vc4_plane_update_lbm().
> > + */
> > if (vc4_state->y_scaling[0] != VC4_SCALING_NONE ||
> > - vc4_state->y_scaling[1] != VC4_SCALING_NONE) {
> > - vc4_dlist_write(vc4_state, vc4_state->lbm.start);
> > - }
> > + vc4_state->y_scaling[1] != VC4_SCALING_NONE)
> > + vc4_state->lbm_offset = vc4_state->dlist_count++;
> >
> > if (num_planes > 1) {
> > /* Emit Cb/Cr as channel 0 and Y as channel
> > @@ -785,13 +806,18 @@ static int vc4_plane_atomic_check(struct drm_plane *plane,
> > struct drm_plane_state *state)
> > {
> > struct vc4_plane_state *vc4_state = to_vc4_plane_state(state);
> > + int ret;
> >
> > vc4_state->dlist_count = 0;
> >
> > - if (plane_enabled(state))
> > - return vc4_plane_mode_set(plane, state);
> > - else
> > + if (!plane_enabled(state))
> > return 0;
> > +
> > + ret = vc4_plane_mode_set(plane, state);
> > + if (ret)
> > + return ret;
> > +
> > + return vc4_plane_update_lbm(state);
> > }
>
> Couldn't you call update_lbm() (maybe called allocate_lbm()) first, and
> then leave the dlist setup as is without needing lbm_offset?
I'll anyway need lbm_offset for the dlist check I do in async_check().
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