[Intel-gfx] [PATCH v12 1/2] drm/i915: Refactor intel_can_enable_sagv

Matt Roper matthew.d.roper at intel.com
Tue Nov 19 23:13:11 UTC 2019


On Fri, Nov 15, 2019 at 04:54:00PM +0200, Stanislav Lisovskiy wrote:
> Currently intel_can_enable_sagv function contains
> a mix of workarounds for different platforms
> some of them are not valid for gens >= 11 already,
> so lets split it into separate functions.
> 
> v2:
>     - Rework watermark calculation algorithm to
>       attempt to calculate Level 0 watermark
>       with added sagv block time latency and
>       check if it fits in DBuf in order to
>       determine if SAGV can be enabled already
>       at this stage, just as BSpec 49325 states.
>       if that fails rollback to usual Level 0
>       latency and disable SAGV.
>     - Remove unneeded tabs(James Ausmus)
> 
> v3: Rebased the patch
> 
> v4: - Added back interlaced check for Gen12 and
>       added separate function for TGL SAGV check
>       (thanks to James Ausmus for spotting)
>     - Removed unneeded gen check
>     - Extracted Gen12 SAGV decision making code
>       to a separate function from skl_compute_wm
> 
> v5: - Added SAGV global state to dev_priv, because
>       we need to track all pipes, not only those
>       in atomic state. Each pipe has now correspondent
>       bit mask reflecting, whether it can tolerate
>       SAGV or not(thanks to Ville Syrjala for suggestions).
>     - Now using active flag instead of enable in crc
>       usage check.
> 
> v6: - Fixed rebase conflicts
> 
> v7: - kms_cursor_legacy seems to get broken because of multiple memcpy
>       calls when copying level 0 water marks for enabled SAGV, to
>       fix this now simply using that field right away, without copying,
>       for that introduced a new wm_level accessor which decides which
>       wm_level to return based on SAGV state.
> 
> v8: - Protect crtc_sagv_mask same way as we do for other global state
>       changes: i.e check if changes are needed, then grab all crtc locks
>       to serialize the changes.
> 
> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at intel.com>
> Cc: James Ausmus <james.ausmus at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c  |  12 +-
>  .../drm/i915/display/intel_display_types.h    |  15 +
>  drivers/gpu/drm/i915/i915_drv.h               |   6 +
>  drivers/gpu/drm/i915/intel_pm.c               | 418 ++++++++++++++++--
>  drivers/gpu/drm/i915/intel_pm.h               |   1 +
>  5 files changed, 409 insertions(+), 43 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index adf50c4b38ad..7f31e33d0b16 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -13401,7 +13401,10 @@ 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]) ||
> +			   (skl_wm_level_equals(&hw_plane_wm->wm[level],

If we cache the result of 'can enable sagv' into the state structure (as
I suggest farther down the patch) then we can just compare with the
right value here rather than trying both.

> +						&sw_plane_wm->sagv_wm0) &&
> +			   (level == 0)))
>  				continue;
>  
>  			DRM_ERROR("mismatch in WM pipe %c plane %d level %d (expected e=%d b=%u l=%u, got e=%d b=%u l=%u)\n",
> @@ -13453,7 +13456,10 @@ 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]) ||
> +			   (skl_wm_level_equals(&hw_plane_wm->wm[level],
> +						&sw_plane_wm->sagv_wm0) &&
> +			   (level == 0)))
>  				continue;
>  
>  			DRM_ERROR("mismatch in WM pipe %c cursor level %d (expected e=%d b=%u l=%u, got e=%d b=%u l=%u)\n",
> @@ -14863,6 +14869,8 @@ static void intel_atomic_commit_tail(struct intel_atomic_state *state)
>  							      new_crtc_state);
>  	}
>  
> +	dev_priv->crtc_sagv_mask = state->crtc_sagv_mask;
> +
>  	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
>  		intel_post_plane_update(old_crtc_state);
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 83ea04149b77..6a300cac883f 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -490,6 +490,20 @@ struct intel_atomic_state {
>  	 */
>  	u8 active_pipe_changes;
>  
> +	/*
> +	 * Contains a mask which reflects whether correspondent pipe
> +	 * can tolerate SAGV or not, so that we can make a decision
> +	 * at atomic_commit_tail stage, whether we enable it or not
> +	 * based on global state in dev_priv.
> +	 */
> +	u32 crtc_sagv_mask;

I feel like your code might flow a bit more naturally if this were
inverted and used as a mask of CRTCs that currently prohibit SAGV?

> +
> +	/*
> +	 * Used to determine if the mask has been already calculated
> +	 * for this state, to avoid unnecessary calculations.
> +	 */
> +	bool crtc_sagv_mask_set;

I think this field can go away too if we just call the function once and
cache the result in the state field.

> +
>  	u8 active_pipes;
>  	/* minimum acceptable cdclk for each pipe */
>  	int min_cdclk[I915_MAX_PIPES];
> @@ -670,6 +684,7 @@ 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;
>  	bool is_planar;
>  };
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1779f600fcfb..0ac9d7b006ca 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1171,6 +1171,12 @@ struct drm_i915_private {
>  
>  	u32 sagv_block_time_us;
>  
> +	/*
> +	 * Contains a bit mask, whether correspondent
> +	 * pipe allows SAGV or not.
> +	 */
> +	u32 crtc_sagv_mask;
> +
>  	struct {
>  		/*
>  		 * Raw watermark latency values:
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 05ba9e1bd247..c914bd1862ba 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3625,13 +3625,9 @@ static bool skl_needs_memory_bw_wa(struct drm_i915_private *dev_priv)
>  	return IS_GEN9_BC(dev_priv) || IS_BROXTON(dev_priv);
>  }
>  
> -static bool
> +bool
>  intel_has_sagv(struct drm_i915_private *dev_priv)
>  {
> -	/* HACK! */
> -	if (IS_GEN(dev_priv, 12))
> -		return false;
> -

The SAGV work you're doing is pretty complicated and this general patch
touches a lot of different platforms (SKL, ICL, TGL, etc.).  It would be
great if we could break this up into a few patches, but if that's not
easy, I'd suggest at least moving this specific change to a final patch
all of its own so that we "flip the switch" on TGL independently of the
general rework.  That way if we wind up with TGL regressions (but no
problems on SKL/ICL) we can just revert a tiny 2-line patch rather than
reverting _all_ of your work here.

>  	return (IS_GEN9_BC(dev_priv) || INTEL_GEN(dev_priv) >= 10) &&
>  		dev_priv->sagv_status != I915_SAGV_NOT_CONTROLLED;
>  }
> @@ -3748,7 +3744,7 @@ intel_disable_sagv(struct drm_i915_private *dev_priv)
>  	return 0;
>  }
>  
> -bool intel_can_enable_sagv(struct intel_atomic_state *state)
> +static void skl_set_sagv_mask(struct intel_atomic_state *state)

Minor nitpick:  I know there's a lot of inconsistent terminology used
throughout the driver, but I always expect functions with names like
'set,' 'update,' etc. to touch hardware somehow.  I prefer naming
functions like this with verbs like 'compute' or 'calc' to make it a bit
more clear (at least in my mind) that we're not doing anything here yet
except analyzing the state.

>  {
>  	struct drm_device *dev = state->base.dev;
>  	struct drm_i915_private *dev_priv = to_i915(dev);
> @@ -3758,29 +3754,35 @@ bool intel_can_enable_sagv(struct intel_atomic_state *state)
>  	enum pipe pipe;
>  	int level, latency;
>  
> +	if (state->crtc_sagv_mask_set)
> +		return;
> +
>  	if (!intel_has_sagv(dev_priv))
> -		return false;
> +		return;

It seems like this check should just be at the top of
intel_can_enable_sagv() rather than duplicated in each platform's
mask-calculating function?

>  
>  	/*
>  	 * If there are no active CRTCs, no additional checks need be performed
>  	 */
>  	if (hweight8(state->active_pipes) == 0)
> -		return true;
> +		return;

This also appears to be a platform-independent check that can move up to
the intel_can_enable_sagv() level?  You don't have it in the TGL
function right now, but it seems like it should apply there as well?

>  
>  	/*
>  	 * SKL+ workaround: bspec recommends we disable SAGV when we have
>  	 * more then one pipe enabled
>  	 */
>  	if (hweight8(state->active_pipes) > 1)
> -		return false;
> +		return;
>  
>  	/* Since we're now guaranteed to only have one active CRTC... */
>  	pipe = ffs(state->active_pipes) - 1;
>  	crtc = intel_get_crtc_for_pipe(dev_priv, pipe);
>  	crtc_state = to_intel_crtc_state(crtc->base.state);
> +	state->crtc_sagv_mask &= ~BIT(crtc->pipe);
>  
> -	if (crtc_state->hw.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE)
> -		return false;
> +	if (crtc_state->hw.adjusted_mode.flags & DRM_MODE_FLAG_INTERLACE) {
> +		state->crtc_sagv_mask_set = true;
> +		return;
> +	}
>  
>  	for_each_intel_plane_on_crtc(dev, crtc, plane) {
>  		struct skl_plane_wm *wm =

In the pre-existing code for this loop (that doesn't show up in the diff
here) it looks like we're looking at the already-committed plane state
to see if the old plane FB was x-tiled...should that be looking at
the new FB from the current state instead?

> @@ -3807,7 +3809,135 @@ bool intel_can_enable_sagv(struct intel_atomic_state *state)
>  		 * incur memory latencies higher than sagv_block_time_us we
>  		 * can't enable SAGV.
>  		 */
> -		if (latency < dev_priv->sagv_block_time_us)
> +		if (latency < dev_priv->sagv_block_time_us) {
> +			state->crtc_sagv_mask_set = true;
> +			return;
> +		}
> +	}
> +
> +	state->crtc_sagv_mask |= BIT(crtc->pipe);
> +	state->crtc_sagv_mask_set = true;
> +}
> +
> +static void tgl_set_sagv_mask(struct intel_atomic_state *state);
> +
> +static void icl_set_sagv_mask(struct intel_atomic_state *state)
> +{
> +	struct drm_device *dev = state->base.dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	struct intel_crtc *crtc;
> +	struct intel_crtc_state *new_crtc_state;
> +	int level, latency;
> +	int i;
> +	int plane_id;
> +
> +	if (state->crtc_sagv_mask_set)
> +		return;
> +
> +	if (!intel_has_sagv(dev_priv))
> +		return;
> +
> +	/*
> +	 * If there are no active CRTCs, no additional checks need be performed
> +	 */
> +	if (hweight8(state->active_pipes) == 0)
> +		return;
> +
> +	for_each_new_intel_crtc_in_state(state, crtc,
> +					     new_crtc_state, i) {
> +		unsigned int flags = crtc->base.state->adjusted_mode.flags;
> +		bool can_sagv;
> +
> +		if (flags & DRM_MODE_FLAG_INTERLACE)
> +			continue;
> +
> +		if (!new_crtc_state->hw.active)
> +			continue;
> +
> +		can_sagv = true;
> +		for_each_plane_id_on_crtc(crtc, plane_id) {
> +			struct skl_plane_wm *wm =
> +				&new_crtc_state->wm.skl.optimal.planes[plane_id];
> +
> +			/* Skip this plane if it's not enabled */
> +			if (!wm->wm[0].plane_en)
> +				continue;
> +
> +			/* Find the highest enabled wm level for this plane */
> +			for (level = ilk_wm_max_level(dev_priv);
> +			     !wm->wm[level].plane_en; --level) {
> +			}
> +
> +			latency = dev_priv->wm.skl_latency[level];
> +
> +			/*
> +			 * If any of the planes on this pipe don't enable
> +			 * wm levels that incur memory latencies higher than
> +			 * sagv_block_time_us we can't enable SAGV.
> +			 */
> +			if (latency < dev_priv->sagv_block_time_us) {
> +				can_sagv = false;
> +				break;
> +			}

I still think this test is a bit problematic.  What if our memory
latency is so low that we can successfully enable all watermark levels,
and the latency for the highest watermark level is still less than ICL's
10us sagv block time?  We might be able to support SAGV just fine, but
we're giving up without actually checking.

Or another case:  say our highest enabled watermark level is 3 with a
latency of 8us.  The next level up, 4, has a latency of 30us which is
high enough that our driver had to disable level 4.  We still don't know
whether the plane could have tolerated the latency of 10us (and there's
a good chance we could have...level 4 in this example was only
impossible because it was such a big latency jump over level 3).

BTW, as I mentioned before, I'm still a bit uncomfortable with the bspec
wording here; I'm going to open a bspec defect to find out for sure how
we should interpret the directions on gen11.

> +		}
> +		if (can_sagv)
> +			state->crtc_sagv_mask |= BIT(crtc->pipe);
> +		else
> +			state->crtc_sagv_mask &= ~BIT(crtc->pipe);
> +	}
> +	state->crtc_sagv_mask_set = true;
> +}
> +
> +bool intel_can_enable_sagv(struct intel_atomic_state *state)
> +{
> +	struct drm_device *dev = state->base.dev;
> +	struct drm_i915_private *dev_priv = to_i915(dev);
> +	int ret, i;
> +	struct intel_crtc *crtc;
> +	struct intel_crtc_state *new_crtc_state;
> +
> +	/*
> +	 * Make sure we always pick global state first,
> +	 * there shouldn't be any issue as we hold only locks
> +	 * to correspondent crtcs in state, however once
> +	 * we detect that we need to change SAGV mask
> +	 * in global state, we will grab all the crtc locks
> +	 * in order to get this serialized, thus other
> +	 * racing commits having other crtc locks, will have
> +	 * to start over again, as stated by Wound-Wait
> +	 * algorithm.
> +	 */
> +	state->crtc_sagv_mask = dev_priv->crtc_sagv_mask;
> +
> +	if (INTEL_GEN(dev_priv) >= 12)
> +		tgl_set_sagv_mask(state);
> +	else if (INTEL_GEN(dev_priv) == 11)
> +		icl_set_sagv_mask(state);
> +	else
> +		skl_set_sagv_mask(state);
> +
> +	/*
> +	 * For SAGV we need to account all the pipes,
> +	 * not only the ones which are in state currently.
> +	 * Grab all locks if we detect that we are actually
> +	 * going to do something.
> +	 */
> +	if (state->crtc_sagv_mask != dev_priv->crtc_sagv_mask) {
> +		ret = intel_atomic_serialize_global_state(state);
> +		if (ret) {
> +			DRM_DEBUG_KMS("Could not serialize global state\n");
> +			return false;
> +		}
> +	}
> +
> +	for_each_new_intel_crtc_in_state(state, crtc, new_crtc_state, i) {
> +		u32 mask = BIT(crtc->pipe);
> +		bool state_sagv_masked = (mask & state->crtc_sagv_mask) == 0;
> +
> +		if (!new_crtc_state->hw.active)
> +			continue;
> +
> +		if (state_sagv_masked)
>  			return false;
>  	}
>  
> @@ -3933,6 +4063,7 @@ static int skl_compute_wm_params(const struct intel_crtc_state *crtc_state,
>  				 int color_plane);
>  static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>  				 int level,
> +				 u32 latency,
>  				 const struct skl_wm_params *wp,
>  				 const struct skl_wm_level *result_prev,
>  				 struct skl_wm_level *result /* out */);
> @@ -3955,7 +4086,10 @@ skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
>  	WARN_ON(ret);
>  
>  	for (level = 0; level <= max_level; level++) {
> -		skl_compute_plane_wm(crtc_state, level, &wp, &wm, &wm);
> +		u32 latency = dev_priv->wm.skl_latency[level];
> +
> +		skl_compute_plane_wm(crtc_state, level, latency, &wp, &wm, &wm);
> +
>  		if (wm.min_ddb_alloc == U16_MAX)
>  			break;
>  
> @@ -4220,6 +4354,98 @@ icl_get_total_relative_data_rate(struct intel_crtc_state *crtc_state,
>  	return total_data_rate;
>  }
>  
> +static int
> +tgl_check_pipe_fits_sagv_wm(struct intel_crtc_state *crtc_state,
> +			    struct skl_ddb_allocation *ddb /* out */)
> +{
> +	struct drm_crtc *crtc = crtc_state->uapi.crtc;
> +	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
> +	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> +	struct skl_ddb_entry *alloc = &crtc_state->wm.skl.ddb;
> +	u16 alloc_size;
> +	u16 total[I915_MAX_PLANES] = {};
> +	u64 total_data_rate;
> +	enum plane_id plane_id;
> +	int num_active;
> +	u64 plane_data_rate[I915_MAX_PLANES] = {};
> +	u32 blocks;
> +
> +	/*
> +	 * No need to check gen here, we call this only for gen12
> +	 */
> +	total_data_rate =
> +		icl_get_total_relative_data_rate(crtc_state,
> +						 plane_data_rate);
> +
> +	skl_ddb_get_pipe_allocation_limits(dev_priv, crtc_state,
> +					   total_data_rate,
> +					   ddb, alloc, &num_active);
> +	alloc_size = skl_ddb_entry_size(alloc);
> +	if (alloc_size == 0)
> +		return -ENOSPC;
> +
> +	/* Allocate fixed number of blocks for cursor. */
> +	total[PLANE_CURSOR] = skl_cursor_allocation(crtc_state, num_active);
> +	alloc_size -= total[PLANE_CURSOR];
> +	crtc_state->wm.skl.plane_ddb_y[PLANE_CURSOR].start =
> +		alloc->end - total[PLANE_CURSOR];
> +	crtc_state->wm.skl.plane_ddb_y[PLANE_CURSOR].end = alloc->end;

All the above is basically a duplication of the pipe's DDB allocation we
have to figure out again later.  Basically our driver used to follow a
sequence of:

        * Calculate DDB (proportional algorithm)
        * Calculate watermarks

and then we switched it to:

        * Calculate watermarks
        * Calculate DDB (need-based algorithm)

If I recall correctly, the need-based DDB algorithm only really needs
the watermark values to divy up the intra-pipe plane DDB allocations so
we could still calculate the overall pipe allocations earlier if we
wanted to.  Doing so would allow you to avoid this duplication of logic:

        * Calculate pipe-level DDB allocations
        * Calculate watermarks
        * Calculate plane-level DDB (need-based algorithm)

> +
> +	/*
> +	 * Do check if we can fit L0 + sagv_block_time and
> +	 * disable SAGV if we can't.
> +	 */
> +	blocks = 0;
> +	for_each_plane_id_on_crtc(intel_crtc, plane_id) {
> +		const struct skl_plane_wm *wm =
> +			&crtc_state->wm.skl.optimal.planes[plane_id];
> +
> +		if (plane_id == PLANE_CURSOR) {
> +			if (WARN_ON(wm->sagv_wm0.min_ddb_alloc >
> +				    total[PLANE_CURSOR])) {
> +				blocks = U32_MAX;
> +				break;
> +			}
> +			continue;
> +		}
> +
> +		blocks += wm->sagv_wm0.min_ddb_alloc;
> +		if (blocks > alloc_size)
> +			return -ENOSPC;
> +	}
> +	return 0;
> +}
> +
> +const struct skl_wm_level *
> +skl_plane_wm_level(struct intel_plane *plane,
> +		const struct intel_crtc_state *crtc_state,
> +		int level,
> +		bool yuv)
> +{
> +	struct drm_atomic_state *state = crtc_state->uapi.state;
> +	enum plane_id plane_id = plane->id;
> +	const struct skl_plane_wm *wm =
> +		&crtc_state->wm.skl.optimal.planes[plane_id];
> +
> +	/*
> +	 * Looks ridicilous but need to check if state is not
> +	 * NULL here as it might be as some cursor plane manipulations
> +	 * seem to happen when no atomic state is actually present,
> +	 * despite crtc_state is allocated. Removing state check
> +	 * from here will result in kernel panic on boot.
> +	 * However we now need to check whether should be use SAGV
> +	 * wm levels here.
> +	 */
> +	if (state) {
> +		struct intel_atomic_state *intel_state =
> +			to_intel_atomic_state(state);
> +		if (intel_can_enable_sagv(intel_state) && !level)

I think we should calculate the 'can enable SAGV' value once and cache
it into a field of the state structure so that you don't have to keep
re-calling this on every single plane/level combination.  Also you can
then use the proper setting to figure out how to verify the hardware
readout value as noted earlier. 

Also one thing I don't see (maybe I'm just overlooking it) is that we
may also need to adjust higher watermark levels upward too:

        "The latency input to the watermark calculation for each level
        must be greater than or equal to the lower level. The latency
        increase to level 0 for SAGV requires the upper levels to be
        adjusted to meet that requirement. Use MIN(latency for this
        level, latency for next lower level) to correct the latency."

Basically it seems like we should just calculate two full sets of
watermark values for all levels and then choose between them at the end?


Matt

> +			return &wm->sagv_wm0;
> +	}
> +
> +	return yuv ? &wm->uv_wm[level] : &wm->wm[level];
> +}
> +
>  static int
>  skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  		      struct skl_ddb_allocation *ddb /* out */)
> @@ -4234,6 +4460,9 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  	u16 uv_total[I915_MAX_PLANES] = {};
>  	u64 total_data_rate;
>  	enum plane_id plane_id;
> +	struct intel_plane *plane;
> +	const struct skl_wm_level *wm_level;
> +	const struct skl_wm_level *wm_uv_level;
>  	int num_active;
>  	u64 plane_data_rate[I915_MAX_PLANES] = {};
>  	u64 uv_plane_data_rate[I915_MAX_PLANES] = {};
> @@ -4285,12 +4514,15 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  	 */
>  	for (level = ilk_wm_max_level(dev_priv); level >= 0; level--) {
>  		blocks = 0;
> -		for_each_plane_id_on_crtc(intel_crtc, plane_id) {
> -			const struct skl_plane_wm *wm =
> -				&crtc_state->wm.skl.optimal.planes[plane_id];
> +		for_each_intel_plane_on_crtc(&dev_priv->drm, intel_crtc, plane) {
> +			plane_id = plane->id;
> +			wm_level = skl_plane_wm_level(plane, crtc_state,
> +						      level, false);
> +			wm_uv_level = skl_plane_wm_level(plane, crtc_state,
> +							 level, true);
>  
>  			if (plane_id == PLANE_CURSOR) {
> -				if (WARN_ON(wm->wm[level].min_ddb_alloc >
> +				if (WARN_ON(wm_level->min_ddb_alloc >
>  					    total[PLANE_CURSOR])) {
>  					blocks = U32_MAX;
>  					break;
> @@ -4298,8 +4530,8 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  				continue;
>  			}
>  
> -			blocks += wm->wm[level].min_ddb_alloc;
> -			blocks += wm->uv_wm[level].min_ddb_alloc;
> +			blocks += wm_level->min_ddb_alloc;
> +			blocks += wm_uv_level->min_ddb_alloc;
>  		}
>  
>  		if (blocks <= alloc_size) {
> @@ -4320,12 +4552,16 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  	 * watermark level, plus an extra share of the leftover blocks
>  	 * proportional to its relative data rate.
>  	 */
> -	for_each_plane_id_on_crtc(intel_crtc, plane_id) {
> -		const struct skl_plane_wm *wm =
> -			&crtc_state->wm.skl.optimal.planes[plane_id];
> +	for_each_intel_plane_on_crtc(&dev_priv->drm, intel_crtc, plane) {
>  		u64 rate;
>  		u16 extra;
>  
> +		plane_id = plane->id;
> +		wm_level = skl_plane_wm_level(plane, crtc_state,
> +					      level, false);
> +		wm_uv_level = skl_plane_wm_level(plane, crtc_state,
> +						 level, true);
> +
>  		if (plane_id == PLANE_CURSOR)
>  			continue;
>  
> @@ -4340,7 +4576,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  		extra = min_t(u16, alloc_size,
>  			      DIV64_U64_ROUND_UP(alloc_size * rate,
>  						 total_data_rate));
> -		total[plane_id] = wm->wm[level].min_ddb_alloc + extra;
> +		total[plane_id] = wm_level->min_ddb_alloc + extra;
>  		alloc_size -= extra;
>  		total_data_rate -= rate;
>  
> @@ -4351,7 +4587,7 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  		extra = min_t(u16, alloc_size,
>  			      DIV64_U64_ROUND_UP(alloc_size * rate,
>  						 total_data_rate));
> -		uv_total[plane_id] = wm->uv_wm[level].min_ddb_alloc + extra;
> +		uv_total[plane_id] = wm_uv_level->min_ddb_alloc + extra;
>  		alloc_size -= extra;
>  		total_data_rate -= rate;
>  	}
> @@ -4392,9 +4628,14 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  	 * that aren't actually possible.
>  	 */
>  	for (level++; level <= ilk_wm_max_level(dev_priv); level++) {
> -		for_each_plane_id_on_crtc(intel_crtc, plane_id) {
> +		for_each_intel_plane_on_crtc(&dev_priv->drm, intel_crtc, plane) {
>  			struct skl_plane_wm *wm =
> -				&crtc_state->wm.skl.optimal.planes[plane_id];
> +				&crtc_state->wm.skl.optimal.planes[plane->id];
> +
> +			wm_level = skl_plane_wm_level(plane, crtc_state,
> +						      level, false);
> +			wm_uv_level = skl_plane_wm_level(plane, crtc_state,
> +						      level, true);
>  
>  			/*
>  			 * We only disable the watermarks for each plane if
> @@ -4408,9 +4649,10 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  			 *  planes must be enabled before the level will be used."
>  			 * So this is actually safe to do.
>  			 */
> -			if (wm->wm[level].min_ddb_alloc > total[plane_id] ||
> -			    wm->uv_wm[level].min_ddb_alloc > uv_total[plane_id])
> -				memset(&wm->wm[level], 0, sizeof(wm->wm[level]));
> +			if (wm_level->min_ddb_alloc > total[plane->id] ||
> +			    wm_uv_level->min_ddb_alloc > uv_total[plane->id])
> +				memset(&wm->wm[level], 0,
> +				       sizeof(struct skl_wm_level));
>  
>  			/*
>  			 * Wa_1408961008:icl, ehl
> @@ -4418,9 +4660,14 @@ skl_allocate_pipe_ddb(struct intel_crtc_state *crtc_state,
>  			 */
>  			if (IS_GEN(dev_priv, 11) &&
>  			    level == 1 && wm->wm[0].plane_en) {
> -				wm->wm[level].plane_res_b = wm->wm[0].plane_res_b;
> -				wm->wm[level].plane_res_l = wm->wm[0].plane_res_l;
> -				wm->wm[level].ignore_lines = wm->wm[0].ignore_lines;
> +				wm_level = skl_plane_wm_level(plane, crtc_state,
> +							      0, false);
> +				wm->wm[level].plane_res_b =
> +					wm_level->plane_res_b;
> +				wm->wm[level].plane_res_l =
> +					wm_level->plane_res_l;
> +				wm->wm[level].ignore_lines =
> +					wm_level->ignore_lines;
>  			}
>  		}
>  	}
> @@ -4649,12 +4896,12 @@ static bool skl_wm_has_lines(struct drm_i915_private *dev_priv, int level)
>  
>  static void skl_compute_plane_wm(const struct intel_crtc_state *crtc_state,
>  				 int level,
> +				 u32 latency,
>  				 const struct skl_wm_params *wp,
>  				 const struct skl_wm_level *result_prev,
>  				 struct skl_wm_level *result /* out */)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
> -	u32 latency = dev_priv->wm.skl_latency[level];
>  	uint_fixed_16_16_t method1, method2;
>  	uint_fixed_16_16_t selected_result;
>  	u32 res_blocks, res_lines, min_ddb_alloc = 0;
> @@ -4775,20 +5022,45 @@ 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,
> +		      bool yuv)
>  {
>  	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 = yuv ? plane_wm->uv_wm : plane_wm->wm;
>  	struct skl_wm_level *result_prev = &levels[0];
>  
>  	for (level = 0; level <= max_level; level++) {
>  		struct skl_wm_level *result = &levels[level];
> +		u32 latency = dev_priv->wm.skl_latency[level];
>  
> -		skl_compute_plane_wm(crtc_state, level, wm_params,
> -				     result_prev, result);
> +		skl_compute_plane_wm(crtc_state, level, latency,
> +				     wm_params, result_prev, result);
>  
>  		result_prev = result;
>  	}
> +	/*
> +	 * 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],
> +		    &plane_wm->sagv_wm0);
> +	} else
> +		memcpy(&plane_wm->sagv_wm0, &levels[0],
> +			sizeof(struct skl_wm_level));
>  }
>  
>  static u32
> @@ -4881,7 +5153,7 @@ 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, false);
>  	skl_compute_transition_wm(crtc_state, &wm_params, wm);
>  
>  	return 0;
> @@ -4903,7 +5175,7 @@ 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, true);
>  
>  	return 0;
>  }
> @@ -5040,10 +5312,13 @@ void skl_write_plane_wm(struct intel_plane *plane,
>  		&crtc_state->wm.skl.plane_ddb_y[plane_id];
>  	const struct skl_ddb_entry *ddb_uv =
>  		&crtc_state->wm.skl.plane_ddb_uv[plane_id];
> +	const struct skl_wm_level *wm_level;
>  
>  	for (level = 0; level <= max_level; level++) {
> +		wm_level = skl_plane_wm_level(plane, crtc_state, level, false);
> +
>  		skl_write_wm_level(dev_priv, PLANE_WM(pipe, plane_id, level),
> -				   &wm->wm[level]);
> +				   wm_level);
>  	}
>  	skl_write_wm_level(dev_priv, PLANE_WM_TRANS(pipe, plane_id),
>  			   &wm->trans_wm);
> @@ -5074,10 +5349,13 @@ void skl_write_cursor_wm(struct intel_plane *plane,
>  		&crtc_state->wm.skl.optimal.planes[plane_id];
>  	const struct skl_ddb_entry *ddb =
>  		&crtc_state->wm.skl.plane_ddb_y[plane_id];
> +	const struct skl_wm_level *wm_level;
>  
>  	for (level = 0; level <= max_level; level++) {
> +		wm_level = skl_plane_wm_level(plane, crtc_state, level, false);
> +
>  		skl_write_wm_level(dev_priv, CUR_WM(pipe, level),
> -				   &wm->wm[level]);
> +				   wm_level);
>  	}
>  	skl_write_wm_level(dev_priv, CUR_WM_TRANS(pipe), &wm->trans_wm);
>  
> @@ -5451,18 +5729,73 @@ static int skl_wm_add_affected_planes(struct intel_atomic_state *state,
>  	return 0;
>  }
>  
> +static void tgl_set_sagv_mask(struct intel_atomic_state *state)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
> +	struct intel_crtc *crtc;
> +	struct intel_crtc_state *new_crtc_state;
> +	struct intel_crtc_state *old_crtc_state;
> +	struct skl_ddb_allocation *ddb = &state->wm_results.ddb;
> +	int ret;
> +	int i;
> +	struct intel_plane *plane;
> +
> +	if (state->crtc_sagv_mask_set)
> +		return;
> +
> +	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
> +					    new_crtc_state, i) {
> +		int pipe_bit = BIT(crtc->pipe);
> +		bool skip = true;
> +
> +		/*
> +		 * If we had set this mast already once for this state,
> +		 * no need to waste CPU cycles for doing this again.
> +		 */
> +		for_each_intel_plane_on_crtc(&dev_priv->drm, crtc, plane) {
> +			enum plane_id plane_id = plane->id;
> +
> +			if (!skl_plane_wm_equals(dev_priv,
> +				&old_crtc_state->wm.skl.optimal.planes[plane_id],
> +				&new_crtc_state->wm.skl.optimal.planes[plane_id])) {
> +				skip = false;
> +				break;
> +			}
> +		}
> +
> +		/*
> +		 * Check if wm levels are actually the same as for previous
> +		 * state, which means we can just skip doing this long check
> +		 * and just  copy correspondent bit from previous state.
> +		 */
> +		if (skip)
> +			continue;
> +
> +		ret = tgl_check_pipe_fits_sagv_wm(new_crtc_state, ddb);
> +		if (!ret)
> +			state->crtc_sagv_mask |= pipe_bit;
> +		else
> +			state->crtc_sagv_mask &= ~pipe_bit;
> +	}
> +	state->crtc_sagv_mask_set = true;
> +}
> +
>  static int
>  skl_compute_wm(struct intel_atomic_state *state)
>  {
>  	struct intel_crtc *crtc;
>  	struct intel_crtc_state *new_crtc_state;
>  	struct intel_crtc_state *old_crtc_state;
> -	struct skl_ddb_values *results = &state->wm_results;
>  	int ret, i;
> +	struct skl_ddb_values *results = &state->wm_results;
> +	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
>  
>  	/* Clear all dirty flags */
>  	results->dirty_pipes = 0;
>  
> +	/* If we exit before check is done */
> +	state->crtc_sagv_mask = dev_priv->crtc_sagv_mask;
> +
>  	ret = skl_ddb_add_affected_pipes(state);
>  	if (ret)
>  		return ret;
> @@ -5638,6 +5971,9 @@ void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
>  				val = I915_READ(CUR_WM(pipe, level));
>  
>  			skl_wm_level_from_reg_val(val, &wm->wm[level]);
> +			if (level == 0)
> +				memcpy(&wm->sagv_wm0, &wm->wm[level],
> +					sizeof(struct skl_wm_level));
>  		}
>  
>  		if (plane_id != PLANE_CURSOR)
> diff --git a/drivers/gpu/drm/i915/intel_pm.h b/drivers/gpu/drm/i915/intel_pm.h
> index b579c724b915..53275860731a 100644
> --- a/drivers/gpu/drm/i915/intel_pm.h
> +++ b/drivers/gpu/drm/i915/intel_pm.h
> @@ -43,6 +43,7 @@ void skl_pipe_wm_get_hw_state(struct intel_crtc *crtc,
>  void g4x_wm_sanitize(struct drm_i915_private *dev_priv);
>  void vlv_wm_sanitize(struct drm_i915_private *dev_priv);
>  bool intel_can_enable_sagv(struct intel_atomic_state *state);
> +bool intel_has_sagv(struct drm_i915_private *dev_priv);
>  int intel_enable_sagv(struct drm_i915_private *dev_priv);
>  int intel_disable_sagv(struct drm_i915_private *dev_priv);
>  bool skl_wm_level_equals(const struct skl_wm_level *l1,
> -- 
> 2.17.1
> 

-- 
Matt Roper
Graphics Software Engineer
VTT-OSGC Platform Enablement
Intel Corporation
(916) 356-2795


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