ISL_AUX_USAGE_CCS_E,
};
+/**
+ * Enum for keeping track of the state an auxiliary compressed surface.
+ *
+ * For any given auxiliary surface compression format (HiZ, CCS, or MCS), any
+ * given slice (lod + array layer) can be in one of the six states described
+ * by this enum. Draw and resolve operations may cause the slice to change
+ * from one state to another. The six valid states are:
+ *
+ * 1) Clear: In this state, each block in the auxiliary surface contains a
+ * magic value that indicates that the block is in the clear state. If
+ * a block is in the clear state, it's values in the primary surface are
+ * ignored and the color of the samples in the block is taken either the
+ * RENDER_SURFACE_STATE packet for color or 3DSTATE_CLEAR_PARAMS for
+ * depth. Since neither the primary surface nor the auxiliary surface
+ * contains the clear value, the surface can be cleared to a different
+ * color by simply changing the clear color without modifying either
+ * surface.
+ *
+ * 2) Compressed w/ Clear: In this state, neither the auxiliary surface
+ * nor the primary surface has a complete representation of the data.
+ * Instead, both surfaces must be used together or else rendering
+ * corruption may occur. Depending on the auxiliary compression format
+ * and the data, any given block in the primary surface may contain all,
+ * some, or none of the data required to reconstruct the actual sample
+ * values. Blocks may also be in the clear state (see Clear) and have
+ * their value taken from outside the surface.
+ *
+ * 3) Compressed w/o Clear: This state is identical to the state above
+ * except that no blocks are in the clear state. In this state, all of
+ * the data required to reconstruct the final sample values is contained
+ * in the auxiliary and primary surface and the clear value is not
+ * considered.
+ *
+ * 4) Resolved: In this state, the primary surface contains 100% of the
+ * data. The auxiliary surface is also valid so the surface can be
+ * validly used with or without aux enabled. The auxiliary surface may,
+ * however, contain non-trivial data and any update to the primary
+ * surface with aux disabled will cause the two to get out of sync.
+ *
+ * 5) Pass-through: In this state, the primary surface contains 100% of the
+ * data and every block in the auxiliary surface contains a magic value
+ * which indicates that the auxiliary surface should be ignored and the
+ * only the primary surface should be considered. Updating the primary
+ * surface without aux works fine and can be done repeatedly in this
+ * mode. Writing to a surface in pass-through mode with aux enabled may
+ * cause the auxiliary buffer to contain non-trivial data and no longer
+ * be in the pass-through state.
+ *
+ * 5) Aux Invalid: In this state, the primary surface contains 100% of the
+ * data and the auxiliary surface is completely bogus. Any attempt to
+ * use the auxiliary surface is liable to result in rendering
+ * corruption. The only thing that one can do to re-enable aux once
+ * this state is reached is to use an ambiguate pass to transition into
+ * the pass-through state.
+ *
+ * Drawing with or without aux enabled may implicitly cause the surface to
+ * transition between these states. There are also four types of auxiliary
+ * compression operations which cause an explicit transition:
+ *
+ * 1) Fast Clear: This operation writes the magic "clear" value to the
+ * auxiliary surface. This operation will safely transition any slice
+ * of a surface from any state to the clear state so long as the entire
+ * slice is fast cleared at once.
+ *
+ * 2) Full Resolve: This operation combines the auxiliary surface data
+ * with the primary surface data and writes the result to the primary.
+ * For HiZ, the docs call this a depth resolve. For CCS, the hardware
+ * full resolve operation does both a full resolve and an ambiguate so
+ * it actually takes you all the way to the pass-through state.
+ *
+ * 3) Partial Resolve: This operation considers blocks which are in the
+ * "clear" state and writes the clear value directly into the primary or
+ * auxiliary surface. Once this operation completes, the surface is
+ * still compressed but no longer references the clear color. This
+ * operation is only available for CCS.
+ *
+ * 4) Ambiguate: This operation throws away the current auxiliary data and
+ * replaces it with the magic pass-through value. If an ambiguate
+ * operation is performed when the primary surface does not contain 100%
+ * of the data, data will be lost. This operation is only implemented
+ * in hardware for depth where it is called a HiZ resolve.
+ *
+ * Not all operations are valid or useful in all states. The diagram below
+ * contains a complete description of the states and all valid and useful
+ * transitions except clear.
+ *
+ * Draw w/ Aux
+ * +----------+
+ * | |
+ * | +-------------+ Draw w/ Aux +-------------+
+ * +------>| Compressed |<---------------------| Clear |
+ * | w/ Clear | | |
+ * +-------------+ +-------------+
+ * | | |
+ * Partial | | |
+ * Resolve | | Full Resolve |
+ * | +----------------------------+ | Full
+ * | | | Resolve
+ * Draw w/ aux | | |
+ * +----------+ | | |
+ * | | \|/ \|/ \|/
+ * | +-------------+ Full Resolve +-------------+
+ * +------>| Compressed |--------------------->| Resolved |
+ * | w/o Clear |<---------------------| |
+ * +-------------+ Draw w/ Aux +-------------+
+ * /|\ | |
+ * | Draw | | Draw
+ * | w/ Aux | | w/o Aux
+ * | Ambiguate | |
+ * | +----------------------------+ |
+ * Draw w/o Aux | | | Draw w/o Aux
+ * +----------+ | | | +----------+
+ * | | | \|/ \|/ | |
+ * | +-------------+ Ambiguate +-------------+ |
+ * +------>| Pass- |<---------------------| Aux |<------+
+ * | through | | Invalid |
+ * +-------------+ +-------------+
+ *
+ *
+ * While the above general theory applies to all forms of auxiliary
+ * compression on Intel hardware, not all states and operations are available
+ * on all compression types. However, each of the auxiliary states and
+ * operations can be fairly easily mapped onto the above diagram:
+ *
+ * HiZ: Hierarchical depth compression is capable of being in any of the
+ * states above. Hardware provides three HiZ operations: "Depth
+ * Clear", "Depth Resolve", and "HiZ Resolve" which map to "Fast
+ * Clear", "Full Resolve", and "Ambiguate" respectively. The
+ * hardware provides no HiZ partial resolve operation so the only way
+ * to get into the "Compressed w/o Clear" state is to render with HiZ
+ * when the surface is in the resolved or pass-through states.
+ *
+ * MCS: Multisample compression is technically capable of being in any of
+ * the states above except that most of them aren't useful. Both the
+ * render engine and the sampler support MCS compression and, apart
+ * from clear color, MCS is format-unaware so we leave the surface
+ * compressed 100% of the time. The hardware provides no MCS
+ * operations.
+ *
+ * CCS_D: Single-sample fast-clears (also called CCS_D in ISL) are one of
+ * the simplest forms of compression since they don't do anything
+ * beyond clear color tracking. They really only support three of
+ * the six states: Clear, Compressed w/ Clear, and Pass-through. The
+ * only CCS_D operation is "Resolve" which maps to a full resolve
+ * followed by an ambiguate.
+ *
+ * CCS_E: Single-sample render target compression (also called CCS_E in ISL)
+ * is capable of being in almost all of the above states. THe only
+ * exception is that it does not have separate resolved and pass-
+ * through states. Instead, the CCS_E full resolve operation does
+ * both a resolve and an ambiguate so it goes directly into the
+ * pass-through state. CCS_E also provides fast clear and partial
+ * resolve operations which work as described above.
+ *
+ * While it is technically possible to perform a CCS_E ambiguate, it
+ * is not provided by Sky Lake hardware so we choose to avoid the aux
+ * invalid state. If the aux invalid state were determined to be
+ * useful, a CCS ambiguate could be done by carefully rendering to
+ * the CCS and filling it with zeros.
+ */
+enum isl_aux_state {
+ ISL_AUX_STATE_CLEAR = 0,
+ ISL_AUX_STATE_COMPRESSED_CLEAR,
+ ISL_AUX_STATE_COMPRESSED_NO_CLEAR,
+ ISL_AUX_STATE_RESOLVED,
+ ISL_AUX_STATE_PASS_THROUGH,
+ ISL_AUX_STATE_AUX_INVALID,
+};
+
/* TODO(chadv): Explain */
enum isl_array_pitch_span {
ISL_ARRAY_PITCH_SPAN_FULL,
projects / mesa.git / commitdiff