radeonsi: fix rendering to tiny viewports where the viewport center is > 8K

This fixes an assertion failure with GL CTS when cts-runner is used.
(not a specific test)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108877
Cc: 18.3 <mesa-stable@lists.freedesktop.org>

diff --git a/src/gallium/drivers/radeonsi/si_state_viewport.c b/src/gallium/drivers/radeonsi/si_state_viewport.c
index 76c56447eb03b8a0147ec6cc88935f76e08fd52f..dac90df1c4f5c120309b388ee6a66be46901538e 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_state_viewport.c
+++ b/src/gallium/drivers/radeonsi/si_state_viewport.c
@@ -146,6 +146,8 @@ static void si_emit_one_scissor(struct si_context *ctx,
                        S_028254_BR_Y(final.maxy));
 }
 
+#define MAX_PA_SU_HARDWARE_SCREEN_OFFSET 8176
+
 static void si_emit_guardband(struct si_context *ctx)
 {
        const struct si_state_rasterizer *rs = ctx->queued.named.rasterizer;
@@ -179,13 +181,12 @@ static void si_emit_guardband(struct si_context *ctx)
        int hw_screen_offset_x = (vp_as_scissor.maxx + vp_as_scissor.minx) / 2;
        int hw_screen_offset_y = (vp_as_scissor.maxy + vp_as_scissor.miny) / 2;
 
-       const unsigned hw_screen_offset_max = 8176;
        /* SI-CI need to align the offset to an ubertile consisting of all SEs. */
        const unsigned hw_screen_offset_alignment =
                ctx->chip_class >= VI ? 16 : MAX2(ctx->screen->se_tile_repeat, 16);
 
-       hw_screen_offset_x = CLAMP(hw_screen_offset_x, 0, hw_screen_offset_max);
-       hw_screen_offset_y = CLAMP(hw_screen_offset_y, 0, hw_screen_offset_max);
+       hw_screen_offset_x = CLAMP(hw_screen_offset_x, 0, MAX_PA_SU_HARDWARE_SCREEN_OFFSET);
+       hw_screen_offset_y = CLAMP(hw_screen_offset_y, 0, MAX_PA_SU_HARDWARE_SCREEN_OFFSET);
 
        /* Align the screen offset by dropping the low bits. */
        hw_screen_offset_x &= ~(hw_screen_offset_alignment - 1);
@@ -332,6 +333,20 @@ static void si_set_viewport_states(struct pipe_context *pctx,
                unsigned h = scissor->maxy - scissor->miny;
                unsigned max_extent = MAX2(w, h);
 
+               unsigned center_x = (scissor->maxx + scissor->minx) / 2;
+               unsigned center_y = (scissor->maxy + scissor->miny) / 2;
+               unsigned max_center = MAX2(center_x, center_y);
+
+               /* PA_SU_HARDWARE_SCREEN_OFFSET can't center viewports whose
+                * center start farther than MAX_PA_SU_HARDWARE_SCREEN_OFFSET.
+                * (for example, a 1x1 viewport in the lower right corner of
+                * 16Kx16K) Such viewports need a greater guardband, so they
+                * have to use a worse quantization mode.
+                */
+               unsigned distance_off_center =
+                       MAX2(0, (int)max_center - MAX_PA_SU_HARDWARE_SCREEN_OFFSET);
+               max_extent += distance_off_center;
+
                /* Determine the best quantization mode (subpixel precision),
                 * but also leave enough space for the guardband.
                 *