radeonsi: explicitly choose center locations for 1xAA on Polaris

Unlike SC, the small primitive filter does not automatically use center
locations in 1xAA mode, so this is needed to avoid artifacts caused by
the small primitive filter discarding triangles that it shouldn't.

As a side effect of how the effective number of samples is now calculated,
this patch also avoids submitting the sample locations for line/poly smoothing
when they're not really needed.

Cc: 12.0 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

1 files changed, 29 insertions, 16 deletions

diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
index 4182906..ee92f15 100644
--- a/src/gallium/drivers/radeonsi/si_state.c
+++ b/src/gallium/drivers/radeonsi/si_state.c
@@ -856,9 +856,13 @@ static void si_bind_rs_state(struct pipe_context *ctx, void *state)
 		return;
 
 	if (sctx->framebuffer.nr_samples > 1 &&
-	    (!old_rs || old_rs->multisample_enable != rs->multisample_enable))
+	    (!old_rs || old_rs->multisample_enable != rs->multisample_enable)) {
 		si_mark_atom_dirty(sctx, &sctx->db_render_state);
 
+		if (sctx->b.family >= CHIP_POLARIS10)
+			si_mark_atom_dirty(sctx, &sctx->msaa_sample_locs.atom);
+	}
+
 	r600_set_scissor_enable(&sctx->b, rs->scissor_enable);
 
 	si_pm4_bind_state(sctx, rasterizer, rs);
@@ -2380,18 +2384,7 @@ static void si_set_framebuffer_state(struct pipe_context *ctx,
 		constbuf.buffer_size = sctx->framebuffer.nr_samples * 2 * 4;
 		si_set_rw_buffer(sctx, SI_PS_CONST_SAMPLE_POSITIONS, &constbuf);
 
-		/* Smoothing (only possible with nr_samples == 1) uses the same
-		 * sample locations as the MSAA it simulates.
-		 *
-		 * Therefore, don't update the sample locations when
-		 * transitioning from no AA to smoothing-equivalent AA, and
-		 * vice versa.
-		 */
-		if ((sctx->framebuffer.nr_samples != 1 ||
-		     old_nr_samples != SI_NUM_SMOOTH_AA_SAMPLES) &&
-		    (sctx->framebuffer.nr_samples != SI_NUM_SMOOTH_AA_SAMPLES ||
-		     old_nr_samples != 1))
-			si_mark_atom_dirty(sctx, &sctx->msaa_sample_locs);
+		si_mark_atom_dirty(sctx, &sctx->msaa_sample_locs.atom);
 	}
 
 	sctx->need_check_render_feedback = true;
@@ -2570,8 +2563,28 @@ static void si_emit_msaa_sample_locs(struct si_context *sctx,
 	struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
 	unsigned nr_samples = sctx->framebuffer.nr_samples;
 
-	cayman_emit_msaa_sample_locs(cs, nr_samples > 1 ? nr_samples :
-						SI_NUM_SMOOTH_AA_SAMPLES);
+	/* Smoothing (only possible with nr_samples == 1) uses the same
+	 * sample locations as the MSAA it simulates.
+	 */
+	if (nr_samples <= 1 && sctx->smoothing_enabled)
+		nr_samples = SI_NUM_SMOOTH_AA_SAMPLES;
+
+	/* The small primitive filter on Polaris requires explicitly setting
+	 * sample locations to 0 when MSAA is disabled.
+	 */
+	if (sctx->b.family >= CHIP_POLARIS10) {
+		struct si_state_rasterizer *rs = sctx->queued.named.rasterizer;
+
+		if (!sctx->smoothing_enabled &&
+		    rs && !rs->multisample_enable)
+			nr_samples = 1;
+	}
+
+	if ((nr_samples > 1 || sctx->b.family >= CHIP_POLARIS10) &&
+	    (nr_samples != sctx->msaa_sample_locs.nr_samples)) {
+		sctx->msaa_sample_locs.nr_samples = nr_samples;
+		cayman_emit_msaa_sample_locs(cs, nr_samples);
+	}
 }
 
 static void si_emit_msaa_config(struct si_context *sctx, struct r600_atom *atom)
@@ -3402,7 +3415,7 @@ void si_init_state_functions(struct si_context *sctx)
 
 	si_init_atom(sctx, &sctx->cache_flush, &sctx->atoms.s.cache_flush, si_emit_cache_flush);
 	si_init_atom(sctx, &sctx->framebuffer.atom, &sctx->atoms.s.framebuffer, si_emit_framebuffer_state);
-	si_init_atom(sctx, &sctx->msaa_sample_locs, &sctx->atoms.s.msaa_sample_locs, si_emit_msaa_sample_locs);
+	si_init_atom(sctx, &sctx->msaa_sample_locs.atom, &sctx->atoms.s.msaa_sample_locs, si_emit_msaa_sample_locs);
 	si_init_atom(sctx, &sctx->db_render_state, &sctx->atoms.s.db_render_state, si_emit_db_render_state);
 	si_init_atom(sctx, &sctx->msaa_config, &sctx->atoms.s.msaa_config, si_emit_msaa_config);
 	si_init_atom(sctx, &sctx->sample_mask.atom, &sctx->atoms.s.sample_mask, si_emit_sample_mask);