Re: [PATCH 2/6] drm/vc4: Move LBM creation out of vc4_plane_mode_set()

[Eric Anholt <eric@anholt.net>]

[-- Attachment #1.1: Type: text/plain, Size: 6048 bytes --]

Boris Brezillon <boris.brezillon@bootlin.com> writes:

> On Thu, 15 Nov 2018 12:39:42 -0800
> Eric Anholt <eric@anholt.net> wrote:
>
>> Boris Brezillon <boris.brezillon@bootlin.com> 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@bootlin.com>
>> > ---
>> >  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().

Fair enough.

Reviewed-by: Eric Anholt <eric@anholt.net>

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel