Mesa (17.1): i965: Stop looking at NewDriverState when emitting 3DSTATE_URB

[Andres Gomez]

Module: Mesa
Branch: 17.1
Commit: 996cd238b81814f81cf94fdd6107faf26d9d0a4b
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=996cd238b81814f81cf94fdd6107faf26d9d0a4b

Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date:   Fri Aug 18 16:10:39 2017 -0700

i965: Stop looking at NewDriverState when emitting 3DSTATE_URB

Looking at NewDriverState is not safe in general.  The state atom system
is set up to ensure that new bits that get added to NewDriverState get
accumulated into the set of bits used when emitting atoms but it doesn't
go the other way.  If we read NewDriverState, we may not get the full
picture because the per-pipeline state (3D or compute) does not get
added to NewDriverState before state emit is done.  It's especially
dangerous to do this from BLORP (either explicitly or implicitly when
BLORP calls gen7_upload_urb) because that does not happen during one of
the normal state upload paths.

This commit solves the problem by whacking all of the per-shader-stage
URB sizes to zero whenever we change the total URB size.  We still have
to flag BRW_NEW_URB_SIZE to ensure that the gen7_urb atom triggers but
the actual decision in gen7_upload_urb can now be based entirely on URB
sizes rather than on state atoms.  This also makes BLORP correct because
it just asks for a new URB config whenever the vsize is too small and so
any change to the total URB size will trigger blorp to re-emit as well
because 0 < vs_entry_size.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>
Bugzilla: https://bugs.freedesktop.org/102289
Cc: mesa-stable at lists.freedesktop.org
(cherry picked from commit d5e217dbfda2a87e149bdc8586c25143fc0ac183)

---

 src/mesa/drivers/dri/i965/gen7_l3_state.c   | 9 +++++++++
 src/mesa/drivers/dri/i965/gen7_urb.c        | 4 +---
 src/mesa/drivers/dri/i965/genX_blorp_exec.c | 3 +--
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/gen7_l3_state.c b/src/mesa/drivers/dri/i965/gen7_l3_state.c
index 536c00c454..53638eb9b8 100644
--- a/src/mesa/drivers/dri/i965/gen7_l3_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_l3_state.c
@@ -204,6 +204,15 @@ update_urb_size(struct brw_context *brw, const struct gen_l3_config *cfg)
    if (brw->urb.size != sz) {
       brw->urb.size = sz;
       brw->ctx.NewDriverState |= BRW_NEW_URB_SIZE;
+
+      /* If we change the total URB size, reset the individual stage sizes to
+       * zero so that, even if there is no URB size change, gen7_upload_urb
+       * still re-emits 3DSTATE_URB_*.
+       */
+      brw->urb.vsize = 0;
+      brw->urb.gsize = 0;
+      brw->urb.hsize = 0;
+      brw->urb.dsize = 0;
    }
 }
 
diff --git a/src/mesa/drivers/dri/i965/gen7_urb.c b/src/mesa/drivers/dri/i965/gen7_urb.c
index 028161df39..0da44e116f 100644
--- a/src/mesa/drivers/dri/i965/gen7_urb.c
+++ b/src/mesa/drivers/dri/i965/gen7_urb.c
@@ -197,9 +197,7 @@ gen7_upload_urb(struct brw_context *brw, unsigned vs_size,
    /* If we're just switching between programs with the same URB requirements,
     * skip the rest of the logic.
     */
-   if (!(brw->ctx.NewDriverState & BRW_NEW_CONTEXT) &&
-       !(brw->ctx.NewDriverState & BRW_NEW_URB_SIZE) &&
-       brw->urb.vsize == entry_size[MESA_SHADER_VERTEX] &&
+   if (brw->urb.vsize == entry_size[MESA_SHADER_VERTEX] &&
        brw->urb.gs_present == gs_present &&
        brw->urb.gsize == entry_size[MESA_SHADER_GEOMETRY] &&
        brw->urb.tess_present == tess_present &&
diff --git a/src/mesa/drivers/dri/i965/genX_blorp_exec.c b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
index 00720f853c..efe75f381e 100644
--- a/src/mesa/drivers/dri/i965/genX_blorp_exec.c
+++ b/src/mesa/drivers/dri/i965/genX_blorp_exec.c
@@ -161,8 +161,7 @@ blorp_emit_urb_config(struct blorp_batch *batch, unsigned vs_entry_size)
    struct brw_context *brw = batch->driver_batch;
 
 #if GEN_GEN >= 7
-   if (!(brw->ctx.NewDriverState & (BRW_NEW_CONTEXT | BRW_NEW_URB_SIZE)) &&
-       brw->urb.vsize >= vs_entry_size)
+   if (brw->urb.vsize >= vs_entry_size)
       return;
 
    brw->ctx.NewDriverState |= BRW_NEW_URB_SIZE;