panfrost: Add debug flag to force packing of AFBC textures on upload

Add `forcepack` flag that will force conversion to AFBC-packed right
after a texture is uploaded when possible. We only pack 2D resources
larger than 32x32 as of now.

Signed-off-by: Louis-Francis Ratté-Boulianne <lfrb@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25012>

src/gallium/drivers/panfrost/pan_resource.c

@@ -387,7 +387,23 @@ panfrost_should_tile_afbc(const struct panfrost_device *dev,
                           const struct panfrost_resource *pres)
 {
    return panfrost_afbc_can_tile(dev) && pres->base.width0 >= 128 &&
-          pres->base.height0 >= 128;
+          pres->base.height0 >= 128 && !(dev->debug & PAN_DBG_FORCE_PACK);
+}
+
+bool
+panfrost_should_pack_afbc(struct panfrost_device *dev,
+                          const struct panfrost_resource *prsrc)
+{
+   const unsigned valid_binding = PIPE_BIND_DEPTH_STENCIL |
+                                  PIPE_BIND_RENDER_TARGET |
+                                  PIPE_BIND_SAMPLER_VIEW;
+
+   return panfrost_afbc_can_pack(prsrc->base.format) && panfrost_is_2d(prsrc) &&
+          drm_is_afbc(prsrc->image.layout.modifier) &&
+          (prsrc->image.layout.modifier & AFBC_FORMAT_MOD_SPARSE) &&
+          (prsrc->base.bind & ~valid_binding) == 0 &&
+          !prsrc->modifier_constant && prsrc->base.width0 >= 32 &&
+          prsrc->base.height0 >= 32;
 }
 
 static bool
@@ -1429,6 +1445,7 @@ panfrost_ptr_unmap(struct pipe_context *pctx, struct pipe_transfer *transfer)
 {
    /* Gallium expects writeback here, so we tile */
 
+   struct panfrost_context *ctx = pan_context(pctx);
    struct panfrost_transfer *trans = pan_transfer(transfer);
    struct panfrost_resource *prsrc =
       (struct panfrost_resource *)transfer->resource;
@@ -1457,8 +1474,13 @@ panfrost_ptr_unmap(struct pipe_context *pctx, struct pipe_transfer *transfer)
          } else {
             pan_blit_from_staging(pctx, trans);
             panfrost_flush_batches_accessing_rsrc(
-               pan_context(pctx), pan_resource(trans->staging.rsrc),
+               ctx, pan_resource(trans->staging.rsrc),
                "AFBC write staging blit");
+
+            if (dev->debug & PAN_DBG_FORCE_PACK) {
+               if (panfrost_should_pack_afbc(dev, prsrc))
+                  panfrost_pack_afbc(ctx, prsrc);
+            }
          }
       }
 

src/gallium/drivers/panfrost/pan_resource.h

@@ -181,6 +181,9 @@ struct panfrost_bo *panfrost_get_afbc_superblock_sizes(
    struct panfrost_context *ctx, struct panfrost_resource *rsrc,
    unsigned first_level, unsigned last_level, unsigned *out_offsets);
 
+bool panfrost_should_pack_afbc(struct panfrost_device *dev,
+                               const struct panfrost_resource *rsrc);
+
 void panfrost_pack_afbc(struct panfrost_context *ctx,
                         struct panfrost_resource *prsrc);
 

src/gallium/drivers/panfrost/pan_screen.c

@@ -72,6 +72,7 @@ static const struct debug_named_value panfrost_debug_options[] = {
    {"overflow",   PAN_DBG_OVERFLOW, "Check for buffer overflows in pool uploads"},
 #endif
    {"yuv",        PAN_DBG_YUV,      "Tint YUV textures with blue for 1-plane and green for 2-plane"},
+   {"forcepack",  PAN_DBG_FORCE_PACK,  "Force packing of AFBC textures on upload"},
    DEBUG_NAMED_VALUE_END
 };
 /* clang-format on */

src/panfrost/lib/pan_afbc.c

@@ -187,6 +187,20 @@ panfrost_afbc_can_ytr(enum pipe_format format)
    return desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB;
 }
 
+/* Only support packing for RGB formats for now. */
+
+bool
+panfrost_afbc_can_pack(enum pipe_format format)
+{
+   const struct util_format_description *desc = util_format_description(format);
+
+   if (desc->nr_channels != 1 && desc->nr_channels != 3 &&
+       desc->nr_channels != 4)
+      return false;
+
+   return desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB;
+}
+
 /*
  * Check if the device supports AFBC with tiled headers (and hence also solid
  * colour blocks).

src/panfrost/lib/pan_texture.h

@@ -233,6 +233,8 @@ enum pan_afbc_mode panfrost_afbc_format(unsigned arch, enum pipe_format format);
 
 bool panfrost_afbc_can_ytr(enum pipe_format format);
 
+bool panfrost_afbc_can_pack(enum pipe_format format);
+
 bool panfrost_afbc_can_tile(const struct panfrost_device *dev);
 
 /*

src/panfrost/lib/pan_util.h

@@ -52,7 +52,8 @@
 #define PAN_DBG_OVERFLOW 0x8000
 #endif
 
-#define PAN_DBG_YUV 0x20000
+#define PAN_DBG_YUV        0x20000
+#define PAN_DBG_FORCE_PACK 0x40000
 
 struct panfrost_device;