[igt-dev] [PATCH v2] lib/igt_fb: Support Tile Size for AMD non linear modifiers.

[Mark Yacoub]

Calculate the width and height of the tile on amdgpu when the modifier
is not linear.

v1:
Change width_ret to bytes not pixels.

Cc: bas at basnieuwenhuizen.nl
Cc: daniel.vetter at ffwll.ch
Signed-off-by: Mark Yacoub <markyacoub at chromium.org>
---
 lib/igt_fb.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/igt_fb.c b/lib/igt_fb.c
index 71b89855..6b926e2e 100644
--- a/lib/igt_fb.c
+++ b/lib/igt_fb.c
@@ -396,6 +396,19 @@ void igt_get_fb_tile_size(int fd, uint64_t modifier, int fb_bpp,
 		vc4_modifier_param = fourcc_mod_broadcom_param(modifier);
 		modifier = fourcc_mod_broadcom_mod(modifier);
 	}
+	// For all non-linear modifiers, AMD uses 64 KiB tiles
+	else if (IS_AMD_FMT_MOD(modifier)) {
+		igt_require_amdgpu(fd);
+		const int bytes_per_pixel = fb_bpp / 8;
+		const int format_log2 = log2(bytes_per_pixel);
+		const int pixel_log2 = log2(64 * 1024) - format_log2;
+		const int width_log2 = (pixel_log2  1) / 2;
+		const int height_log2 = pixel_log2 - width_log2;
+
+		*width_ret = bytes_per_pixel << width_log2;
+		*height_ret = 1 << height_log2;
+		return;
+	}
 
 	switch (modifier) {
 	case LOCAL_DRM_FORMAT_MOD_NONE:
-- 
2.32.0.288.g62a8d224e6-goog