[PATCH] drm/i915: Add the predicate source registers to the register whitelist

From: Neil Roberts <neil@linux.intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH] drm/i915: Add the predicate source registers to the register whitelist
Date: Fri,  7 Nov 2014 15:34:31 +0000	[thread overview]
Message-ID: <1415374471-29992-1-git-send-email-neil@linux.intel.com> (raw)

The predicate source registers are needed to implement conditional
rendering without stalling. The two source registers are used to load
the previous values of the PS_DEPTH_COUNT register saved from
PIPE_CONTROL commands. These can then be compared and used to set the
predicate enable bit via the MI_PREDICATE command.

Signed-off-by: Neil Roberts <neil@linux.intel.com>
---

There is a corresponding patch for Mesa which is using these registers
on the mailing list here:

http://lists.freedesktop.org/archives/mesa-dev/2014-November/070347.html

There are some other registers such as MI_PREDICATE_DATA which can be
used for more advanced predicate checking but I haven't added them to
the list because they aren't needed to implement
GL_NV_conditional_render.

 drivers/gpu/drm/i915/i915_cmd_parser.c | 2 ++
 drivers/gpu/drm/i915/i915_reg.h        | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 4c35e2a..9732155 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -408,6 +408,8 @@ static const u32 gen7_render_regs[] = {
 	REG64(PS_INVOCATION_COUNT),
 	REG64(PS_DEPTH_COUNT),
 	OACONTROL, /* Only allowed for LRI and SRM. See below. */
+	REG64(MI_PREDICATE_SRC0),
+	REG64(MI_PREDICATE_SRC1),
 	GEN7_3DPRIM_END_OFFSET,
 	GEN7_3DPRIM_START_VERTEX,
 	GEN7_3DPRIM_VERTEX_COUNT,
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ea84e1e..9275d41 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -314,6 +314,8 @@
 #define   MI_BATCH_GTT		    (2<<6) /* aliased with (1<<7) on gen4 */
 #define MI_BATCH_BUFFER_START_GEN8	MI_INSTR(0x31, 1)
 
+#define MI_PREDICATE_SRC0	(0x2400)
+#define MI_PREDICATE_SRC1	(0x2408)
 
 #define MI_PREDICATE_RESULT_2	(0x2214)
 #define  LOWER_SLICE_ENABLED	(1<<0)
-- 
1.9.3

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