[Mesa-dev] [PATCH] nouveau: make sure there's always room to emit a fence

[Ilia Mirkin]

I started seeing a lot of situations on nv30 where fence emission
wouldn't fit into the previous buffer (causing assertions). This ensures
that whenever checking for space, we always leave a bit of extra room
for the fence emission commands. Adjusts the nv30 and nvc0 fence
emission logic to bypass the space checking as well.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Cc: mesa-stable at lists.freedesktop.org
---
 src/gallium/drivers/nouveau/nouveau_winsys.h   | 2 ++
 src/gallium/drivers/nouveau/nv30/nv30_screen.c | 4 +++-
 src/gallium/drivers/nouveau/nv50/nv50_screen.c | 1 +
 src/gallium/drivers/nouveau/nvc0/nvc0_screen.c | 3 ++-
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/nouveau/nouveau_winsys.h b/src/gallium/drivers/nouveau/nouveau_winsys.h
index 389a229..a44fd3e 100644
--- a/src/gallium/drivers/nouveau/nouveau_winsys.h
+++ b/src/gallium/drivers/nouveau/nouveau_winsys.h
@@ -24,6 +24,8 @@ PUSH_AVAIL(struct nouveau_pushbuf *push)
 static inline bool
 PUSH_SPACE(struct nouveau_pushbuf *push, uint32_t size)
 {
+   /* Provide a buffer so that fences always have room to be emitted */
+   size += 8;
    if (PUSH_AVAIL(push) < size)
       return nouveau_pushbuf_space(push, size, 0, 0) == 0;
    return true;
diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
index 39267b3..335c163 100644
--- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
+++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
@@ -347,7 +347,9 @@ nv30_screen_fence_emit(struct pipe_screen *pscreen, uint32_t *sequence)
 
    *sequence = ++screen->base.fence.sequence;
 
-   BEGIN_NV04(push, NV30_3D(FENCE_OFFSET), 2);
+   assert(PUSH_AVAIL(push) >= 3);
+   PUSH_DATA (push, NV30_3D_FENCE_OFFSET |
+              (2 /* size */ << 18) | (7 /* subchan */ << 13));
    PUSH_DATA (push, 0);
    PUSH_DATA (push, *sequence);
 }
diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
index 6012ff6..812b246 100644
--- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
+++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
@@ -388,6 +388,7 @@ nv50_screen_fence_emit(struct pipe_screen *pscreen, u32 *sequence)
    /* we need to do it after possible flush in MARK_RING */
    *sequence = ++screen->base.fence.sequence;
 
+   assert(PUSH_AVAIL(push) >= 5);
    PUSH_DATA (push, NV50_FIFO_PKHDR(NV50_3D(QUERY_ADDRESS_HIGH), 4));
    PUSH_DATAh(push, screen->fence.bo->offset);
    PUSH_DATA (push, screen->fence.bo->offset);
diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
index 32da76c..afd91e6 100644
--- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
+++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
@@ -537,7 +537,8 @@ nvc0_screen_fence_emit(struct pipe_screen *pscreen, u32 *sequence)
    /* we need to do it after possible flush in MARK_RING */
    *sequence = ++screen->base.fence.sequence;
 
-   BEGIN_NVC0(push, NVC0_3D(QUERY_ADDRESS_HIGH), 4);
+   assert(PUSH_AVAIL(push) >= 5);
+   PUSH_DATA (push, NVC0_FIFO_PKHDR_SQ(NVC0_3D(QUERY_ADDRESS_HIGH), 4));
    PUSH_DATAh(push, screen->fence.bo->offset);
    PUSH_DATA (push, screen->fence.bo->offset);
    PUSH_DATA (push, *sequence);
-- 
2.4.9