etnaviv: use dummy RT buffer when rendering without color buffer

At least GC2000 seems to push some dirt from the PE color cache into
the last bound render target when drawing depth only. Newer cores
seem to behave properly and don't do this, but I have found no way
to fix it on GC2000. Flushes and stalls don't seem to make any
difference.

In order to stop the core from pushing the dirt into a precious real
render target, plug in dummy buffer when rendering without a color
buffer.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

diff --git a/src/gallium/drivers/etnaviv/etnaviv_context.c b/src/gallium/drivers/etnaviv/etnaviv_context.c
index 3038d210e1096f148c073251ade22624dfbf2c2f..1c305d82a0fc321dce1544421ddff086b6dc9dad 100644 (file)
--- a/src/gallium/drivers/etnaviv/etnaviv_context.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_context.c
@@ -60,6 +60,9 @@ etna_context_destroy(struct pipe_context *pctx)
 {
    struct etna_context *ctx = etna_context(pctx);
 
+   if (ctx->dummy_rt)
+      etna_bo_del(ctx->dummy_rt);
+
    if (ctx->primconvert)
       util_primconvert_destroy(ctx->primconvert);
 
@@ -486,6 +489,16 @@ etna_context_create(struct pipe_screen *pscreen, void *priv, unsigned flags)
    slab_create_child(&ctx->transfer_pool, &screen->transfer_pool);
    list_inithead(&ctx->active_hw_queries);
 
+   /* create dummy RT buffer, used when rendering with no color buffer */
+   ctx->dummy_rt = etna_bo_new(ctx->screen->dev, 64 * 64 * 4,
+                               DRM_ETNA_GEM_CACHE_WC);
+   if (!ctx->dummy_rt)
+      goto fail;
+
+   ctx->dummy_rt_reloc.bo = ctx->dummy_rt;
+   ctx->dummy_rt_reloc.offset = 0;
+   ctx->dummy_rt_reloc.flags = ETNA_RELOC_READ | ETNA_RELOC_WRITE;
+
    return pctx;
 
 fail:

diff --git a/src/gallium/drivers/etnaviv/etnaviv_context.h b/src/gallium/drivers/etnaviv/etnaviv_context.h
index 584caa77080b1256395abc521eab096f00a1ea35..6ad9f3431e15e38f3c36f7d05c074a4ba38e96b4 100644 (file)
--- a/src/gallium/drivers/etnaviv/etnaviv_context.h
+++ b/src/gallium/drivers/etnaviv/etnaviv_context.h
@@ -190,6 +190,9 @@ struct etna_context {
 
    /* list of active hardware queries */
    struct list_head active_hw_queries;
+
+   struct etna_bo *dummy_rt;
+   struct etna_reloc dummy_rt_reloc;
 };
 
 static inline struct etna_context *

diff --git a/src/gallium/drivers/etnaviv/etnaviv_state.c b/src/gallium/drivers/etnaviv/etnaviv_state.c
index 87ba10b0dc9870d137eded966dd93d441c60ace5..006bf3016812b59b838fc45d28d22d80522c43a0 100644 (file)
--- a/src/gallium/drivers/etnaviv/etnaviv_state.c
+++ b/src/gallium/drivers/etnaviv/etnaviv_state.c
@@ -191,8 +191,9 @@ etna_set_framebuffer_state(struct pipe_context *pctx,
       cs->TS_COLOR_STATUS_BASE.bo = NULL;
       cs->TS_COLOR_SURFACE_BASE.bo = NULL;
 
-      for (int i = 0; i < ETNA_MAX_PIXELPIPES; i++)
-         cs->PE_PIPE_COLOR_ADDR[i].bo = NULL;
+      cs->PE_COLOR_ADDR = ctx->dummy_rt_reloc;
+      for (int i = 0; i < ctx->specs.pixel_pipes; i++)
+         cs->PE_PIPE_COLOR_ADDR[i] = ctx->dummy_rt_reloc;
    }
 
    if (sv->zsbuf != NULL) {