src/daedalus_core.c

@@ -53,6 +53,25 @@ daedalus_ctx *daedalus_ctx_create(void)
 
 daedalus_ctx *daedalus_ctx_create_no_qpu(void)
 {
+    /*
+     * Per the "QPU is default substrate" decree 2026-05-23:
+     * setting DAEDALUS_FORCE_QPU=1 in the process env escalates this
+     * function to a full daedalus_ctx_create(), letting the libavcodec
+     * substitution shims (which call create_no_qpu via pthread_once)
+     * fire the V3D shaders that exist for cycles 1/2/4/5/8.  Without
+     * this hook each consumer process (firefox, mpv, daemon) would
+     * need its own shim build to opt into QPU.
+     *
+     * Default behaviour (env var unset / not "1") is unchanged: pure
+     * NEON ctx, no implicit Vulkan init.  Firefox / mpv consumers
+     * that dlopen libavcodec without opting in stay on the
+     * Vulkan-free path; the daemon explicitly sets
+     * DAEDALUS_FORCE_QPU=1 before loading libavcodec.
+     */
+    const char *force = getenv("DAEDALUS_FORCE_QPU");
+    if (force && force[0] == '1' && force[1] == 0)
+        return daedalus_ctx_create();
+
     daedalus_ctx *ctx = calloc(1, sizeof(*ctx));
     if (!ctx) return NULL;
     ctx->has_qpu = 0;
@@ -84,16 +103,25 @@ void daedalus_ctx_destroy(daedalus_ctx *ctx)
 
 daedalus_substrate daedalus_recipe_substrate_for(daedalus_kernel k)
 {
+    /*
+     * Recipe table per the "QPU is default substrate" decree
+     * 2026-05-23.  Any kernel that has a V3D compute shader returns
+     * SUBSTRATE_QPU; CPU is the fallback for kernels without a
+     * shader (still the case for H.264 IDCT 4x4 / IDCT 8x8 / qpel
+     * mc20 — covered by follow-on task 165).  The dispatch
+     * wrappers already fall back to CPU automatically when the
+     * ctx doesn't have QPU available (daedalus_ctx_has_qpu == 0).
+     */
     switch (k) {
     case DAEDALUS_KERNEL_VP9_IDCT8:        return DAEDALUS_SUBSTRATE_QPU;
     case DAEDALUS_KERNEL_VP9_LPF4_INNER:   return DAEDALUS_SUBSTRATE_QPU;
-    case DAEDALUS_KERNEL_VP9_MC_8H:        return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_VP9_MC_8H:        return DAEDALUS_SUBSTRATE_QPU;	/* v3d_mc_8h.spv */
     case DAEDALUS_KERNEL_VP9_LPF8_INNER:   return DAEDALUS_SUBSTRATE_QPU;
-    case DAEDALUS_KERNEL_AV1_CDEF_8X8:     return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_AV1_CDEF_8X8:     return DAEDALUS_SUBSTRATE_QPU;	/* v3d_cdef.spv */
-    case DAEDALUS_KERNEL_H264_IDCT4:       return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_H264_IDCT4:       return DAEDALUS_SUBSTRATE_CPU;	/* TODO task #165 */
-    case DAEDALUS_KERNEL_H264_IDCT8:       return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_H264_IDCT8:       return DAEDALUS_SUBSTRATE_CPU;	/* TODO task #165 */
-    case DAEDALUS_KERNEL_H264_DEBLOCK_LV:  return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_H264_DEBLOCK_LV:  return DAEDALUS_SUBSTRATE_QPU;	/* v3d_h264deblock.spv */
-    case DAEDALUS_KERNEL_H264_QPEL_MC20:   return DAEDALUS_SUBSTRATE_CPU;
+    case DAEDALUS_KERNEL_H264_QPEL_MC20:   return DAEDALUS_SUBSTRATE_CPU;	/* TODO task #165 */
     }
     return DAEDALUS_SUBSTRATE_CPU;
 }