[Mesa-dev] [PATCH] radv: Unset ZRANGE_PRECISION when depth was zeroed

[James Legg]

This avoids bug 105396 somehow. I suspect it is a VI and GFX9 hardware
bug which PAL calls WaTcCompatZRange, but I don't know for sure.

In the VK_FORMAT_D32_SFLOAT case, TILE_STENCIL_DISABLE is not set for
tc compatible image formats regardless of not having a stencil aspect.
If TILE_STENCIL_DISABLE was set, ZRANGE_PRECISION would have no effect
and the bug would occur again.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105396
CC: <mesa-stable at lists.freedesktop.org>
CC: Dave Airlie <airlied at redhat.com>
CC: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
CC: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/vulkan/radv_cmd_buffer.c | 52 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/src/amd/vulkan/radv_cmd_buffer.c b/src/amd/vulkan/radv_cmd_buffer.c
index 3e0ed0e9a9..89e31a0347 100644
--- a/src/amd/vulkan/radv_cmd_buffer.c
+++ b/src/amd/vulkan/radv_cmd_buffer.c
@@ -915,6 +915,37 @@ radv_emit_fb_ds_state(struct radv_cmd_buffer *cmd_buffer,
 
 	}
 
+	if (image->surface.htile_size)
+	{
+		/* If the last depth clear value was 0.0f, set ZRANGE_PRECISION
+		 * to 0 in dp_z_info for more accuracy with reverse depth; and
+		 * to avoid https://bugs.freedesktop.org/show_bug.cgi?id=105396.
+		 * Otherwise, we leave it set to 1.
+		 */
+		radeon_emit(cmd_buffer->cs, PKT3(PKT3_COND_WRITE, 7, 0));
+
+		const uint32_t write_space = 0 << 8;	/* register */
+		const uint32_t poll_space = 1 << 4;	/* memory */
+		const uint32_t function = 3 << 0;	/* equal to the reference */
+		const uint32_t options = write_space | poll_space | function;
+		radeon_emit(cmd_buffer->cs, options);
+
+		/* poll address - location of the depth clear value */
+		uint64_t va = radv_buffer_get_va(image->bo);
+		va += image->offset + image->clear_value_offset;
+		radeon_emit(cmd_buffer->cs, va);
+		radeon_emit(cmd_buffer->cs, va >> 32);
+
+		radeon_emit(cmd_buffer->cs, fui(0.0f));		/* reference value */
+		radeon_emit(cmd_buffer->cs, (uint32_t)-1);	/* comparison mask */
+		radeon_emit(cmd_buffer->cs, R_028040_DB_Z_INFO >> 2); /* write address low */
+		radeon_emit(cmd_buffer->cs, 0u);		/* write address high */
+
+		/* The value to write data when the condition passes */
+		uint32_t db_z_info_clear_zero = db_z_info & C_028040_ZRANGE_PRECISION;
+		radeon_emit(cmd_buffer->cs, db_z_info_clear_zero);
+	}
+
 	radeon_set_context_reg(cmd_buffer->cs, R_028B78_PA_SU_POLY_OFFSET_DB_FMT_CNTL,
 			       ds->pa_su_poly_offset_db_fmt_cntl);
 }
@@ -3479,7 +3510,8 @@ void radv_CmdEndRenderPass(
 
 /*
  * For HTILE we have the following interesting clear words:
- *   0xfffff30f: Uncompressed, full depth range, for depth+stencil HTILE
+ *   0xfffff30f: Uncompressed, full depth range, for depth+stencil HTILE when ZRANGE_PRECISION is 1
+ *   0x0003f30f: Uncompressed, full depth range, for depth+stencil HTILE when ZRANGE_PRECISION is 0
  *   0xfffc000f: Uncompressed, full depth range, for depth only HTILE.
  *   0xfffffff0: Clear depth to 1.0
  *   0x00000000: Clear depth to 0.0
@@ -3528,8 +3560,22 @@ static void radv_handle_depth_image_transition(struct radv_cmd_buffer *cmd_buffe
 		radv_initialize_htile(cmd_buffer, image, range, 0);
 	} else if (!radv_layout_is_htile_compressed(image, src_layout, src_queue_mask) &&
 	           radv_layout_is_htile_compressed(image, dst_layout, dst_queue_mask)) {
-		uint32_t clear_value = vk_format_is_stencil(image->vk_format) ? 0xfffff30f : 0xfffc000f;
-		radv_initialize_htile(cmd_buffer, image, range, clear_value);
+	        if (vk_format_is_stencil(image->vk_format)) {
+			/* The appropriate clear value depends on DB_Z_INFO's
+			 * ZRANGE_PRECISION, which can vary depending on the
+			 * last used clear value, which could be from another
+			 * command buffer. Instead of picking the appropriate
+			 * clear value on the GPU, resummarize accurately.
+			 */
+			VkImageSubresourceRange local_range = *range;
+			local_range.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT;
+			local_range.baseMipLevel = 0;
+			local_range.levelCount = 1;
+
+			radv_resummarize_depth_image_inplace(cmd_buffer, image, &local_range);
+		} else {
+			radv_initialize_htile(cmd_buffer, image, range, 0xfffc000f);
+		}
 	} else if (radv_layout_is_htile_compressed(image, src_layout, src_queue_mask) &&
 	           !radv_layout_is_htile_compressed(image, dst_layout, dst_queue_mask)) {
 		VkImageSubresourceRange local_range = *range;
-- 
2.14.3