Field Name Bits Default Description HIZ_ENABLE 0 0x0 Enables hierarchical Z. POSSIBLE VALUES: 00 - Hierarchical Z Disabled 01 - Hierarchical Z Enabled HIZ_MIN 1 0x0 POSSIBLE VALUES: 00 - Update Hierarchical Z with Max value 01 - Update Hierarchical Z with Min value FAST_FILL 2 0x0 POSSIBLE VALUES: 00 - Fast Fill Disabled 01 - Fast Fill Enabled (ZB_DEPTHCLEARVALUE ) RD_COMP_ENABLE 3 0x0 Enables reading of compressed Z data from memory to the cache. POSSIBLE VALUES: 00 - Z Read Compression Disabled 01 - Z Read Compression Enabled WR_COMP_ENABLE 4 0x0 Enables writing of compressed Z data from cache to memory, POSSIBLE VALUES: 00 - Z Write Compression Disabled 01 - Z Write Compression Enabled ZB_CB_CLEAR 5 0x0 This bit is set when the Z buffer is used to help the CB in clearing a region. Part of the region is cleared by the color buffer and part will be cleared by the Z buffer. Since the Z buffer does not have any write masks in the cache, full micro- tiles need to be written. If a partial micro-tile is touched, then the un-touched part will be unknowns. The cache will operate in write-allocate mode and quads will be accumulated in the cache and then evicted to main memory. The color value is supplied through the ZB_DEPTHCLEARVALUE register. POSSIBLE VALUES: 00 - Z unit cache controller does RMW 01 - Z unit cache controller does cache-line granular Write only FORCE_COMPRESSED_STENCIL_VALUE 6 0x0 Enabling this bit will force all the compressed stencil values to be equal to old_stencil_value&~ZB_STENCILREFMASK.stencilwritemask | ZB_STENCILREFMASK.stencilref&ZB_STENCILREFMASK.stencilwritemask. This should be enabled during stencil clears to avoid needless decompression. POSSIBLE VALUES: 00 - Do not force the compressed stencil value. 01 - Force the compressed stencil value. ZEQUAL_OPTIMIZE_DISABLE 7 0x0 By default this is 0 (enabled). When NEWZ=OLDZ, then writes do not occur to save BW. POSSIBLE VALUES: 00 - Enable not updating the Z buffer if NewZ=OldZ 01 - Disable above feature (in case there is a bug) SEQUAL_OPTIMIZE_DISABLE 8 0x0 By default this is 0 (enabled). When NEW_STENCIL=OLD_STENCIL, then writes do not occur to save BW. POSSIBLE VALUES: 00 - Enable not updating the Stencil buffer if NewS=OldS 01 - Disable above feature (in case there is a bug) BMASK_DISABLE 10 0x0 Controls whether bytemasking is used or not. POSSIBLE VALUES: 00 - Enable bytemasking 01 - Disable bytemasking HIZ_EQUAL_REJECT_ENABLE 11 0x0 Enables hiz rejects when the z function is equals. POSSIBLE VALUES: 00 - Disable 01 - Enable HIZ_FP_EXP_BITS 14:12 0x0 Number of exponent bits to use for the hiz floating point format. Values 0 to 5 are legal. 0 will disable the floating point hiz encoding. HIZ_FP_INVERT 15 0x0 Determines whether leading zeros or ones are eliminated. POSSIBLE VALUES: 00 - Count leading 1s 01 - Count leading 0s TILE_OVERWRITE_RECOMPRESSION_DISABLE 16 0x0 The zb tries to detect single plane equations that completely overwrite a compressed tile. This allows the tile to jump from the decompressed state to the fully compressed state. POSSIBLE VALUES: 00 - Enable tile overwrite recompression 01 - Disable tile overwrite recompression CONTIGUOUS_6XAA_SAMPLES_DISABLE 17 0x0 This disables storing samples contiguously in 6xaa. POSSIBLE VALUES: 00 - Enable contiguous samples 01 - Disable contiguous samples PEQ_PACKING_ENABLE 18 0x0 Enables packing of the plane equations to eliminate wasted peq slots. POSSIBLE VALUES: 00 - Disable 01 - Enable COVERED_PTR_MASKING_ENABLE 19 0x0 Enables discarding of pointers from pixels that are going to be covered. This reduces the apparent number of plane equations in use. POSSIBLE VALUES: 00 - Disable 01 - Enable