The console's DCC of a single-level 4-byte SW_64KB_R_X surface is
ceil(W/512) * ceil(H/512) * 4096 bytes, 49152 for 1920x1080, but the
driver stored and read one key per 256 surface bytes (34560).
PPSA26344 retiles its render DCC into the displayable copy it
registers (cs_dcc_retile_32bpp); a retile of the stale tail gives the
mixed keys PPSA12544 stops on.
DccKeyCount gives that extent. Color target and storage image key
stores cover it when the DCC is pipe-aligned (CB_COLOR_ATTRIB3 bit 30,
T# word 6 bit 19), whose CB keys reach its last meta block, and throw
where it is not writable; unaligned DCC keeps one key per 256 bytes,
as do texture and color target key reads. DisplayBufferKeys reads the
display DCC over the extent, presents only when every key agrees,
names the first differing key's pixels and checks a pending image
against those keys.
sceVideoOutRegisterBuffers2 threw "DCC presentation is not implemented"
for category 1 (DCC-compressed) buffers, which PPSA26344 registers. Such
a buffer now needs DCC metadata and the tiled layout, and dcc_control may
only use the CB_DCC_CONTROL block layout bits 0x10026c.
At a flip the keys are read behind their recorded writers, one byte per
256 bytes as in the driver's DCC model. Uncompressed keys present the
stored texels as before; a uniform clear code presents its color with a
GPU clear of the scaler's source image; a pending storage image is used
when it serves the keys. Mixed or unreadable keys, clear codes the
display format has no DCC encoding for, register-clear keys over a
pending image and a clear color wider than 32 bits throw. Buffers
without DCC take the old path.
Celegans12