Mesa (master): i965/hsw: Implement end of batch workaround

[Ben Widawsky]

Module: Mesa
Branch: master
Commit: 0166b4c165271bd7525a91049e58e390cb596c60
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0166b4c165271bd7525a91049e58e390cb596c60

Author: Ben Widawsky <benjamin.widawsky at intel.com>
Date:   Thu Jul  9 10:35:19 2015 -0700

i965/hsw: Implement end of batch workaround

This patch can cause an infinite recursion if the previous patch titled, "i965:
Track finished batch state" isn't present (backporters take notice).

v2: Sent out the wrong patch originally. This patches switches the order of
flushes, doing the generic flush before the CC_STATE, and the required
workaround flush afterwards

v3: Only perform workaround for render ring
Add text to the BATCH_RESERVE comments

v4 (By Ken): Rebase; update citation to mention PRM and Wa name; combine two
blocks.

http://otc-mesa-ci.jf.intel.com/job/bwidawsk/171/

Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/mesa/drivers/dri/i965/intel_batchbuffer.c |   27 +++++++++++++++++++++++--
 src/mesa/drivers/dri/i965/intel_batchbuffer.h |    4 ++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
index 969d92c..d93ee6e 100644
--- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
+++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
@@ -32,6 +32,7 @@
 #include "intel_buffers.h"
 #include "intel_fbo.h"
 #include "brw_context.h"
+#include "brw_defines.h"
 
 #include <xf86drm.h>
 #include <i915_drm.h>
@@ -206,10 +207,32 @@ brw_finish_batch(struct brw_context *brw)
     */
    brw_emit_query_end(brw);
 
-   /* We may also need to snapshot and disable OA counters. */
-   if (brw->batch.ring == RENDER_RING)
+   if (brw->batch.ring == RENDER_RING) {
+      /* We may also need to snapshot and disable OA counters. */
       brw_perf_monitor_finish_batch(brw);
 
+      if (brw->is_haswell) {
+         /* From the Haswell PRM, Volume 2b, Command Reference: Instructions,
+          * 3DSTATE_CC_STATE_POINTERS > "Note":
+          *
+          * "SW must program 3DSTATE_CC_STATE_POINTERS command at the end of every
+          *  3D batch buffer followed by a PIPE_CONTROL with RC flush and CS stall."
+          *
+          * From the example in the docs, it seems to expect a regular pipe control
+          * flush here as well. We may have done it already, but meh.
+          *
+          * See also WaAvoidRCZCounterRollover.
+          */
+         brw_emit_mi_flush(brw);
+         BEGIN_BATCH(2);
+         OUT_BATCH(_3DSTATE_CC_STATE_POINTERS << 16 | (2 - 2));
+         OUT_BATCH(brw->cc.state_offset | 1);
+         ADVANCE_BATCH();
+         brw_emit_pipe_control_flush(brw, PIPE_CONTROL_RENDER_TARGET_FLUSH |
+                                          PIPE_CONTROL_CS_STALL);
+      }
+   }
+
    /* Mark that the current program cache BO has been used by the GPU.
     * It will be reallocated if we need to put new programs in for the
     * next batch.
diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.h b/src/mesa/drivers/dri/i965/intel_batchbuffer.h
index fdd07e0..8eaedd1 100644
--- a/src/mesa/drivers/dri/i965/intel_batchbuffer.h
+++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.h
@@ -26,6 +26,10 @@ extern "C" {
  *     - 3 DWords for MI_REPORT_PERF_COUNT itself on Gen6+.  ==> 12 bytes.
  *       On Ironlake, it's 6 DWords, but we have some slack due to the lack of
  *       Sandybridge PIPE_CONTROL madness.
+ *   - CC_STATE workaround on HSW (12 * 4 = 48 bytes)
+ *     - 5 dwords for initial mi_flush
+ *     - 2 dwords for CC state setup
+ *     - 5 dwords for the required pipe control at the end
  */
 #define BATCH_RESERVED 152