[Mesa-dev] [PATCH 1/4] radeonsi: fix DCC fast clear for luminance and alpha formats

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

I reproduced this bug on Polaris11 and Raven.

I can't get this bug on Fiji. The reason might be that Fiji doesn't use
2D tiling for the test due to higher 2D tiling alignment requirements.

Fixes piglit: spec at ext_framebuffer_object@fbo-fast-clear
---
 src/gallium/drivers/radeon/r600_texture.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/gallium/drivers/radeon/r600_texture.c b/src/gallium/drivers/radeon/r600_texture.c
index d0492d6..f74bbce 100644
--- a/src/gallium/drivers/radeon/r600_texture.c
+++ b/src/gallium/drivers/radeon/r600_texture.c
@@ -2404,39 +2404,48 @@ static void evergreen_set_clear_color(struct r600_texture *rtex,
 static bool vi_get_fast_clear_parameters(enum pipe_format surface_format,
 					 const union pipe_color_union *color,
 					 uint32_t* reset_value,
 					 bool* clear_words_needed)
 {
 	bool values[4] = {};
 	int i;
 	bool main_value = false;
 	bool extra_value = false;
 	int extra_channel;
+
+	/* This is needed to get the correct DCC clear value for luminance formats.
+	 * 1) Get the linear format (because the next step can't handle L8_SRGB).
+	 * 2) Convert luminance to red. (the real hw format for luminance)
+	 */
+	surface_format = util_format_linear(surface_format);
+	surface_format = util_format_luminance_to_red(surface_format);
+
 	const struct util_format_description *desc = util_format_description(surface_format);
 
 	if (desc->block.bits == 128 &&
 	    (color->ui[0] != color->ui[1] ||
 	     color->ui[0] != color->ui[2]))
 		return false;
 
 	*clear_words_needed = true;
 	*reset_value = 0x20202020U;
 
 	/* If we want to clear without needing a fast clear eliminate step, we
 	 * can set each channel to 0 or 1 (or 0/max for integer formats). We
 	 * have two sets of flags, one for the last or first channel(extra) and
 	 * one for the other channels(main).
 	 */
 
 	if (surface_format == PIPE_FORMAT_R11G11B10_FLOAT ||
 	    surface_format == PIPE_FORMAT_B5G6R5_UNORM ||
-	    surface_format == PIPE_FORMAT_B5G6R5_SRGB) {
+	    surface_format == PIPE_FORMAT_B5G6R5_SRGB ||
+	    util_format_is_alpha(surface_format)) {
 		extra_channel = -1;
 	} else if (desc->layout == UTIL_FORMAT_LAYOUT_PLAIN) {
 		if(r600_translate_colorswap(surface_format, false) <= 1)
 			extra_channel = desc->nr_channels - 1;
 		else
 			extra_channel = 0;
 	} else
 		return true;
 
 	for (i = 0; i < 4; ++i) {
-- 
2.7.4