r300g: fix some bugs with zbuffer compression (v4)

This drops the memblock manager for ZMASK. Instead, only one zbuffer can be
compressed at a time. Note that this does not necessarily have to be slower.
When there is a large number of zbuffers, compression might be used more often
than it was before. It's also easier to debug.

How it works:
1) 'clear' turns the compression on.
2) If some other zbuffer is set or the currently-bound zbuffer is used
   for texturing, the driver decompresses it and then turns the compression off.

Notes:
- The ZMASK clear has been refactored, so that only one packet3 is used to clear
  ZMASK.
- The 8x8 compression mode is disabled. I couldn't make it work without issues.
- Also removed driver-specific stuff from u_blitter.

Driver status:
- RV530 and R580 appear to just work (finally).
- RV570 should work, but there may be an issue that we don't correctly
  calculate the number of dwords to clear, resulting in a partially
  uninitialized zbuffer.
- RS690 misrenders as if no ZMASK clear happened. No idea what's going on.
- RV350 may even hardlock. This issue was already present and this patch doesn't
  fix it.

I think we are still missing some hardware info we need to make the zbuffer
compression work fully.

Note that there is also an issue with HiZ, resulting in a sort of blocky
zigzagged corruption around some objects.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/gallium/drivers/r300/r300_chipset.h b/src/gallium/drivers/r300/r300_chipset.h
index f2035d2009..0be161fa07 100644
--- a/src/gallium/drivers/r300/r300_chipset.h
+++ b/src/gallium/drivers/r300/r300_chipset.h
@@ -33,6 +33,13 @@
 #define PIPE_ZMASK_SIZE 4096
 #define RV3xx_ZMASK_SIZE 5120
 
+/* The size of a compressed tile. Each compressed tile takes 2 bits
+ * in the ZMASK RAM, so there is always 16 tiles per one dword. */
+enum r300_zmask_compression {
+   R300_ZCOMP_4X4 = 4,
+   R300_ZCOMP_8X8 = 8
+};
+
 /* Structure containing all the possible information about a specific Radeon
  * in the R3xx, R4xx, and R5xx families. */
 struct r300_capabilities {
@@ -50,10 +57,12 @@ struct r300_capabilities {
     unsigned num_tex_units;
     /* Whether or not TCL is physically present */
     boolean has_tcl;
-    /* Some chipsets do not have HiZ RAM - other have varying amounts . */
+    /* Some chipsets do not have HiZ RAM - other have varying amounts. */
     int hiz_ram;
-    /*  some chipsets have zmask ram per pipe some don't */
+    /* Some chipsets have zmask ram per pipe some don't. */
     int zmask_ram;
+    /* Compression mode for ZMASK. */
+    enum r300_zmask_compression z_compress;
     /* Whether or not this is RV350 or newer, including all r400 and r500
      * chipsets. The differences compared to the oldest r300 chips are:
      * - Blend LTE/GTE thresholds