Re: [Intel-gfx] [PATCH v27 3/6] drm/i915: Add TGL+ SAGV support

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, May 06, 2020 at 03:12:10PM +0300, Lisovskiy, Stanislav wrote:
> On Wed, May 06, 2020 at 12:12:28PM +0300, Ville Syrjälä wrote:
> > On Wed, May 06, 2020 at 11:31:05AM +0300, Lisovskiy, Stanislav wrote:
> > > On Tue, May 05, 2020 at 01:59:11PM +0300, Ville Syrjälä wrote:
> > > > On Tue, May 05, 2020 at 01:22:44PM +0300, Stanislav Lisovskiy wrote:
> > > > > Starting from TGL we need to have a separate wm0
> > > > > values for SAGV and non-SAGV which affects
> > > > > how calculations are done.
> > > > > 
> > > > > v2: Remove long lines
> > > > > v3: Removed COLOR_PLANE enum references
> > > > > v4, v5, v6: Fixed rebase conflict
> > > > > 
> > > > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> > > > > ---
> > > > >  drivers/gpu/drm/i915/display/intel_display.c  |   8 +-
> > > > >  .../drm/i915/display/intel_display_types.h    |   3 +
> > > > >  drivers/gpu/drm/i915/intel_pm.c               | 128 +++++++++++++++++-
> > > > >  3 files changed, 130 insertions(+), 9 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> > > > > index fd6d63b03489..be5741cb7595 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display.c
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> > > > > @@ -13961,7 +13961,9 @@ static void verify_wm_state(struct intel_crtc *crtc,
> > > > >  		/* Watermarks */
> > > > >  		for (level = 0; level <= max_level; level++) {
> > > > >  			if (skl_wm_level_equals(&hw_plane_wm->wm[level],
> > > > > -						&sw_plane_wm->wm[level]))
> > > > > +						&sw_plane_wm->wm[level]) ||
> > > > > +			    (level == 0 && skl_wm_level_equals(&hw_plane_wm->wm[level],
> > > > > +							       &sw_plane_wm->sagv_wm0)))
> > > > >  				continue;
> > > > >  
> > > > >  			drm_err(&dev_priv->drm,
> > > > > @@ -14016,7 +14018,9 @@ static void verify_wm_state(struct intel_crtc *crtc,
> > > > >  		/* Watermarks */
> > > > >  		for (level = 0; level <= max_level; level++) {
> > > > >  			if (skl_wm_level_equals(&hw_plane_wm->wm[level],
> > > > > -						&sw_plane_wm->wm[level]))
> > > > > +						&sw_plane_wm->wm[level]) ||
> > > > > +			    (level == 0 && skl_wm_level_equals(&hw_plane_wm->wm[level],
> > > > > +							       &sw_plane_wm->sagv_wm0)))
> > > > >  				continue;
> > > > >  
> > > > >  			drm_err(&dev_priv->drm,
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > index 9488449e4b94..32cbbf7dddc6 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > > > @@ -688,11 +688,14 @@ struct skl_plane_wm {
> > > > >  	struct skl_wm_level wm[8];
> > > > >  	struct skl_wm_level uv_wm[8];
> > > > >  	struct skl_wm_level trans_wm;
> > > > > +	struct skl_wm_level sagv_wm0;
> > > > > +	struct skl_wm_level uv_sagv_wm0;
> > > > 
> > > > As mentioned before uv_wm is not a thing on icl+, so nuke this.
> > > 
> > > This is used in skl_plane_wm_level accessor, which is used for all
> > > platforms, not just icl+. I remember we had agreed that for all platforms
> > > before tgl I simply copy sagv_wm0 values from regular wm0, so that this
> > > behaviour is unified(remember that your comment about memcpy which I changed
> > > to assignment, see skl_compute_sagv_wm). 
> > 
> > I think having that duplicated is just making things more confusing.
> > Also uv_wm is never used by the hardware even on pre-icl, so having
> > the accessor thing use it for the hw programming just doesn't make
> > any sense.
> 
> Problem is that we use it in skl_allocate_pipe_ddb in a few places:
> 
> blocks += wm_level->min_ddb_alloc;
> blocks += wm_uv_level->min_ddb_alloc;

I don't think we should need any accessor in there. If we do
what I suggested earlier, which I think was something like
(can't find the mail anymore unfortunately):

for reverse wm levels {
	blocks = sum(wm[level] blocks for all planes) +
		sum(uv_wm[level] blocks for all planes)
	...
	if (block <= alloc_size)
		break;
}

if (level < 0)
	fail;

blocks_sagv = sum(sagv_wm blocks for all planes)
if (blocks_sagv > blocks && blocks_sagv <= alloc_size) {
    blocks = blocks_sagv;
    use_sagv_wm = true;
} else {
    use_sagv_wm = false;
}
alloc_size -= blocks;

for_each_plane_id() {
	total = use_sagv_wm ? sagv_wm.min_ddb_alloc :
		wm[level].min_ddb_alloc;
	...
}



> 
> then those plane data rates:
> 
> rate = plane_data_rate[plane_id];
> extra = min_t(u16, alloc_size,
>       DIV64_U64_ROUND_UP(alloc_size * rate, total_data_rate));
> total[plane_id] = wm_level->min_ddb_alloc + extra;
> alloc_size -= extra;
> total_data_rate -= rate;
> 
> if (total_data_rate == 0)
> 	break;
> 
> rate = uv_plane_data_rate[plane_id];
> extra = min_t(u16, alloc_size,
>       DIV64_U64_ROUND_UP(alloc_size * rate, total_data_rate));
> 
> uv_total[plane_id] = wm_uv_level->min_ddb_alloc + extra;
> 
> So if I remove this wm_uv from skl_plane_wm_level accessor,
> the logic in skl_allocate_pipe_ddb will obvisouly change?
> 
> 
> Stan
> 
> 
> > 
> > For the compute side I think all we should really need is
> > something like:
> > 
> > tgl_compute_sagv_wm()
> > {
> > 	skl_compute_wm_level(sagv_wm0, latency + whatever);
> > }
> > 
> > skl_build_plane_wm_single()
> > {
> > 	...
> > 	skl_compute_transition_wm();
> > +	if (gen >= 12)
> > +		tgl_compute_sagv_wm();
> > }
> > 
> > And for the progamming side we should just pick the right
> > wm0 based on the crtc_state->use_sagv_wm or whatever flag.
> > 
> > > 
> > > So if I remove it and this is called for pre-icl platforms, guess this would still
> > > need wm_uv data?
> > > 
> > > 
> > > Stan
> > > 
> > > > 
> > > > >  	bool is_planar;
> > > > >  };
> > > > >  
> > > > >  struct skl_pipe_wm {
> > > > >  	struct skl_plane_wm planes[I915_MAX_PLANES];
> > > > > +	bool can_sagv;
> > > > 
> > > > I would call it use_sagv_wm or somesuch to make it actually clear what
> > > > it does.
> > > > 
> > > > >  };
> > > > >  
> > > > >  enum vlv_wm_level {
> > > > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > > > > index c7d726a656b2..1b9925b6672c 100644
> > > > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > > > @@ -3871,6 +3871,9 @@ static bool icl_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state)
> > > > >  	return intel_crtc_can_enable_sagv(crtc_state);
> > > > >  }
> > > > >  
> > > > > +static bool
> > > > > +tgl_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state);
> > > > > +
> > > > >  bool intel_can_enable_sagv(const struct intel_bw_state *bw_state)
> > > > >  {
> > > > >  	if (bw_state->active_pipes && !is_power_of_2(bw_state->active_pipes))
> > > > > @@ -3884,7 +3887,7 @@ static int intel_compute_sagv_mask(struct intel_atomic_state *state)
> > > > >  	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> > > > >  	int ret;
> > > > >  	struct intel_crtc *crtc;
> > > > > -	const struct intel_crtc_state *new_crtc_state;
> > > > > +	struct intel_crtc_state *new_crtc_state;
> > > > >  	struct intel_bw_state *new_bw_state = NULL;
> > > > >  	const struct intel_bw_state *old_bw_state = NULL;
> > > > >  	int i;
> > > > > @@ -3899,7 +3902,9 @@ static int intel_compute_sagv_mask(struct intel_atomic_state *state)
> > > > >  
> > > > >  		old_bw_state = intel_atomic_get_old_bw_state(state);
> > > > >  
> > > > > -		if (INTEL_GEN(dev_priv) >= 11)
> > > > > +		if (INTEL_GEN(dev_priv) >= 12)
> > > > > +			can_sagv = tgl_crtc_can_enable_sagv(new_crtc_state);
> > > > > +		else if (INTEL_GEN(dev_priv) >= 11)
> > > > >  			can_sagv = icl_crtc_can_enable_sagv(new_crtc_state);
> > > > >  		else
> > > > >  			can_sagv = skl_crtc_can_enable_sagv(new_crtc_state);
> > > > > @@ -3921,6 +3926,24 @@ static int intel_compute_sagv_mask(struct intel_atomic_state *state)
> > > > >  			return ret;
> > > > >  	}
> > > > >  
> > > > > +	for_each_new_intel_crtc_in_state(state, crtc,
> > > > > +					 new_crtc_state, i) {
> > > > > +		struct skl_pipe_wm *pipe_wm = &new_crtc_state->wm.skl.optimal;
> > > > > +
> > > > > +		/*
> > > > > +		 * Due to drm limitation at commit state, when
> > > > > +		 * changes are written the whole atomic state is
> > > > > +		 * zeroed away => which prevents from using it,
> > > > > +		 * so just sticking it into pipe wm state for
> > > > > +		 * keeping it simple - anyway this is related to wm.
> > > > > +		 * Proper way in ideal universe would be of course not
> > > > > +		 * to lose parent atomic state object from child crtc_state,
> > > > > +		 * and stick to OOP programming principles, which had been
> > > > > +		 * scientifically proven to work.
> > > > 
> > > > Seems like random ramblings. I'd just nuke the comment.
> > > > 
> > > > > +		 */
> > > > > +		pipe_wm->can_sagv = intel_can_enable_sagv(new_bw_state);
> > > > > +	}
> > > > > +
> > > > >  	if (intel_can_enable_sagv(new_bw_state) != intel_can_enable_sagv(old_bw_state)) {
> > > > >  		ret = intel_atomic_serialize_global_state(&new_bw_state->base);
> > > > >  		if (ret)
> > > > > @@ -4664,12 +4687,39 @@ skl_plane_wm_level(const struct intel_crtc_state *crtc_state,
> > > > >  		   int level,
> > > > >  		   int color_plane)
> > > > >  {
> > > > > -	const struct skl_plane_wm *wm =
> > > > > -		&crtc_state->wm.skl.optimal.planes[plane_id];
> > > > > +	const struct skl_pipe_wm *pipe_wm = &crtc_state->wm.skl.optimal;
> > > > > +	const struct skl_plane_wm *wm = &pipe_wm->planes[plane_id];
> > > > > +
> > > > > +	if (!level) {
> > > > > +		if (pipe_wm->can_sagv)
> > > > > +			return color_plane == 0 ? &wm->sagv_wm0 : &wm->uv_sagv_wm0;
> > > > > +	}
> > > > >  
> > > > >  	return color_plane == 0 ? &wm->wm[level] : &wm->uv_wm[level];
> > > > >  }
> > > > >  
> > > > > +static bool
> > > > > +tgl_crtc_can_enable_sagv(const struct intel_crtc_state *crtc_state)
> > > > > +{
> > > > > +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> > > > > +	enum plane_id plane_id;
> > > > > +
> > > > > +	if (!crtc_state->hw.active)
> > > > > +		return true;
> > > > > +
> > > > > +	for_each_plane_id_on_crtc(crtc, plane_id) {
> > > > > +		const struct skl_ddb_entry *plane_alloc =
> > > > > +			&crtc_state->wm.skl.plane_ddb_y[plane_id];
> > > > > +		const struct skl_plane_wm *wm =
> > > > > +			&crtc_state->wm.skl.optimal.planes[plane_id];
> > > > > +
> > > > > +		if (skl_ddb_entry_size(plane_alloc) < wm->sagv_wm0.min_ddb_alloc)
> > > > > +			return false;
> > > > > +	}
> > > > > +
> > > > > +	return true;
> > > > > +}
> > > > > +
> > > > >  static int
> > > > >  skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state)
> > > > >  {
> > > > > @@ -5251,10 +5301,17 @@ static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
> > > > >  static void
> > > > >  skl_compute_wm_levels(const struct intel_crtc_state *crtc_state,
> > > > >  		      const struct skl_wm_params *wm_params,
> > > > > -		      struct skl_wm_level *levels)
> > > > > +		      struct skl_plane_wm *plane_wm,
> > > > > +		      int color_plane)
> > > > >  {
> > > > >  	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> > > > >  	int level, max_level = ilk_wm_max_level(dev_priv);
> > > > > +	/*
> > > > > +	 * Check which kind of plane is it and based on that calculate
> > > > > +	 * correspondent WM levels.
> > > > > +	 */
> > > > > +	struct skl_wm_level *levels = color_plane == 1 ?
> > > > > +				      plane_wm->uv_wm : plane_wm->wm;
> > > > >  	struct skl_wm_level *result_prev = &levels[0];
> > > > >  
> > > > >  	for (level = 0; level <= max_level; level++) {
> > > > > @@ -5268,6 +5325,40 @@ skl_compute_wm_levels(const struct intel_crtc_state *crtc_state,
> > > > >  	}
> > > > >  }
> > > > >  
> > > > > +static void skl_compute_sagv_wm(const struct intel_crtc_state *crtc_state,
> > > > > +				const struct skl_wm_params *wm_params,
> > > > > +				struct skl_plane_wm *plane_wm,
> > > > > +				int color_plane)
> > > > > +{
> > > > > +	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> > > > > +	struct skl_wm_level *sagv_wm = color_plane == 1 ?
> > > > > +				&plane_wm->uv_sagv_wm0 : &plane_wm->sagv_wm0;
> > > > > +	struct skl_wm_level *levels = color_plane == 1 ?
> > > > > +				plane_wm->uv_wm : plane_wm->wm;
> > > > > +
> > > > > +	/*
> > > > > +	 * For Gen12 if it is an L0 we need to also
> > > > > +	 * consider sagv_block_time when calculating
> > > > > +	 * L0 watermark - we will need that when making
> > > > > +	 * a decision whether enable SAGV or not.
> > > > > +	 * For older gens we agreed to copy L0 value for
> > > > > +	 * compatibility.
> > > > > +	 */
> > > > > +	if ((INTEL_GEN(dev_priv) >= 12)) {
> > > > > +		u32 latency = dev_priv->wm.skl_latency[0];
> > > > > +
> > > > > +		latency += dev_priv->sagv_block_time_us;
> > > > > +		skl_compute_plane_wm(crtc_state, 0, latency,
> > > > > +				     wm_params, &levels[0],
> > > > > +				     sagv_wm);
> > > > > +		DRM_DEBUG_KMS("%d L0 blocks required for SAGV vs %d for non-SAGV\n",
> > > > > +			      sagv_wm->min_ddb_alloc, levels[0].min_ddb_alloc);
> > > > > +	} else {
> > > > > +		/* Since all members are POD */
> > > > > +		*sagv_wm = levels[0];
> > > > > +	}
> > > > > +}
> > > > > +
> > > > >  static void skl_compute_transition_wm(const struct intel_crtc_state *crtc_state,
> > > > >  				      const struct skl_wm_params *wp,
> > > > >  				      struct skl_plane_wm *wm)
> > > > > @@ -5344,7 +5435,8 @@ static int skl_build_plane_wm_single(struct intel_crtc_state *crtc_state,
> > > > >  	if (ret)
> > > > >  		return ret;
> > > > >  
> > > > > -	skl_compute_wm_levels(crtc_state, &wm_params, wm->wm);
> > > > > +	skl_compute_wm_levels(crtc_state, &wm_params, wm, 0);
> > > > > +	skl_compute_sagv_wm(crtc_state, &wm_params, wm, 0);
> > > > >  	skl_compute_transition_wm(crtc_state, &wm_params, wm);
> > > > >  
> > > > >  	return 0;
> > > > > @@ -5366,7 +5458,8 @@ static int skl_build_plane_wm_uv(struct intel_crtc_state *crtc_state,
> > > > >  	if (ret)
> > > > >  		return ret;
> > > > >  
> > > > > -	skl_compute_wm_levels(crtc_state, &wm_params, wm->uv_wm);
> > > > > +	skl_compute_wm_levels(crtc_state, &wm_params, wm, 1);
> > > > > +	skl_compute_sagv_wm(crtc_state, &wm_params, wm, 1);
> > > > >  
> > > > >  	return 0;
> > > > >  }
> > > > > @@ -5751,6 +5844,12 @@ skl_print_wm_changes(struct intel_atomic_state *state)
> > > > >  				    enast(new_wm->wm[7].ignore_lines), new_wm->wm[7].plane_res_l,
> > > > >  				    enast(new_wm->trans_wm.ignore_lines), new_wm->trans_wm.plane_res_l);
> > > > >  
> > > > > +			drm_dbg_kms(&dev_priv->drm,
> > > > > +				    "[PLANE:%d:%s] sagv wm0 lines %4d -> %4d\n",
> > > > > +				    plane->base.base.id, plane->base.name,
> > > > > +				    old_wm->sagv_wm0.plane_res_l,
> > > > > +				    new_wm->sagv_wm0.plane_res_l);
> > > > > +
> > > > >  			drm_dbg_kms(&dev_priv->drm,
> > > > >  				    "[PLANE:%d:%s]  blocks %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d"
> > > > >  				    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d\n",
> > > > > @@ -5766,6 +5865,12 @@ skl_print_wm_changes(struct intel_atomic_state *state)
> > > > >  				    new_wm->wm[6].plane_res_b, new_wm->wm[7].plane_res_b,
> > > > >  				    new_wm->trans_wm.plane_res_b);
> > > > >  
> > > > > +			drm_dbg_kms(&dev_priv->drm,
> > > > > +				    "[PLANE:%d:%s] sagv wm0 blocks %4d -> %4d\n",
> > > > > +				    plane->base.base.id, plane->base.name,
> > > > > +				    old_wm->sagv_wm0.plane_res_b,
> > > > > +				    new_wm->sagv_wm0.plane_res_b);
> > > > > +
> > > > >  			drm_dbg_kms(&dev_priv->drm,
> > > > >  				    "[PLANE:%d:%s] min_ddb %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d"
> > > > >  				    " -> %4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d,%4d\n",
> > > > > @@ -5780,6 +5885,12 @@ skl_print_wm_changes(struct intel_atomic_state *state)
> > > > >  				    new_wm->wm[4].min_ddb_alloc, new_wm->wm[5].min_ddb_alloc,
> > > > >  				    new_wm->wm[6].min_ddb_alloc, new_wm->wm[7].min_ddb_alloc,
> > > > >  				    new_wm->trans_wm.min_ddb_alloc);
> > > > > +
> > > > > +			drm_dbg_kms(&dev_priv->drm,
> > > > > +				    "[PLANE:%d:%s] sagv wm0 min ddb %4d -> %4d\n",
> > > > > +				    plane->base.base.id, plane->base.name,
> > > > > +				    old_wm->sagv_wm0.min_ddb_alloc,
> > > > > +				    new_wm->sagv_wm0.min_ddb_alloc);
> > > > >  		}
> > > > >  	}
> > > > >  }
> > > > > @@ -6072,6 +6183,9 @@ void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
> > > > >  			skl_wm_level_from_reg_val(val, &wm->wm[level]);
> > > > >  		}
> > > > >  
> > > > > +		memcpy(&wm->sagv_wm0, &wm->wm[0],
> > > > > +		       sizeof(struct skl_wm_level));
> > > > > +
> > > > >  		if (plane_id != PLANE_CURSOR)
> > > > >  			val = I915_READ(PLANE_WM_TRANS(pipe, plane_id));
> > > > >  		else
> > > > > -- 
> > > > > 2.24.1.485.gad05a3d8e5
> > > > 
> > > > -- 
> > > > Ville Syrjälä
> > > > Intel
> > 
> > -- 
> > Ville Syrjälä
> > Intel

-- 
Ville Syrjälä
Intel
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