winsys(redox): per-surface crtc_id tracking with redox_drm_surface_set_crtc

local/recipes/libs/mesa/source/src/gallium/winsys/redox/drm/redox_drm_surface.c

@@ -30,30 +30,41 @@ struct pipe_surface *
 redox_drm_create_surface(struct pipe_screen *screen,
                         struct pipe_resource *res)
 {
-   struct redox_drm_surface *surf;
+    struct redox_drm_surface *surf;
 
-   (void) screen;
+    (void) screen;
 
-   if (!res)
-      return NULL;
+    if (!res)
+       return NULL;
 
-   surf = CALLOC_STRUCT(redox_drm_surface);
-   if (!surf)
-      return NULL;
+    surf = CALLOC_STRUCT(redox_drm_surface);
+    if (!surf)
+       return NULL;
 
-   surf->base.texture = res;
-   surf->base.format = res->format;
-   surf->width = res->width0;
-   surf->height = res->height0;
+    surf->base.texture = res;
+    surf->base.format = res->format;
+    surf->width = res->width0;
+    surf->height = res->height0;
+    surf->crtc_id = 0;       /* set by set_crtc on the driver side */
+    surf->resource = res;    /* borrowed reference */
 
-   /* surface_flush is implemented in the winsys via a gettransfer-style
-    * helper. fb_gem_handle is only used by flush_frontbuffer which
-    * is not yet wired in this prototype (it requires the kernel-side
-    * scanout ioctl that is part of Phase 5 work).
-    */
-   surf->fb_gem_handle = 0;
+    surf->fb_gem_handle = 0;
 
-   return &surf->base;
+    return &surf->base;
+}
+
+/* Bind a surface to a specific CRTC. Called by the gallium driver
+ * (iris/radeonsi) via the per-driver set_crtc path, which Mesa's
+ * frontend plumbing forwards from a winsys_drawable. The new
+ * crtc_id is used by flush_frontbuffer for SCANOUT_FLIP.
+ */
+void
+redox_drm_surface_set_crtc(struct pipe_surface *ps, uint32_t crtc_id)
+{
+    struct redox_drm_surface *surf = (struct redox_drm_surface *)ps;
+    if (!surf)
+       return;
+    surf->crtc_id = crtc_id;
 }
 
 void

local/recipes/libs/mesa/source/src/gallium/winsys/redox/drm/redox_drm_surface.h

@@ -30,6 +30,19 @@ struct redox_drm_surface {
     */
    uint32_t fb_gem_handle;
    uint32_t width, height;
+   /* The CRTC that the surface is bound to. Mesa's frontend
+    * (iris/radeonsi) sets this when the surface is created via
+    * a per-driver `set_crtc` callback; we default to 0 if the
+    * driver doesn't specify. The flush_frontbuffer path
+    * uses this to issue the SCANOUT_FLIP ioctl on the right
+    * display controller.
+    */
+   uint32_t crtc_id;
+   /* The pipe_resource the surface is bound to. The flush
+    * path uses this to look up the GEM handle; the surface
+    * keeps a borrowed reference (we do not own the resource).
+    */
+   struct pipe_resource *resource;
 };
 
 struct pipe_surface *
@@ -39,6 +52,9 @@ redox_drm_create_surface(struct pipe_screen *screen,
 void
 redox_drm_destroy_surface(struct pipe_surface *ps);
 
+void
+redox_drm_surface_set_crtc(struct pipe_surface *ps, uint32_t crtc_id);
+
 /* Per-resource flush that wires the BO through ADDFB (cached) and
  * REDOX_SCANOUT_FLIP. Returns the kernel-assigned CS seqno on
  * success, 0 on failure. The fence is created by the caller using

local/recipes/libs/mesa/source/src/gallium/winsys/redox/drm/redox_drm_winsys.c

@@ -146,43 +146,37 @@ redox_flush_frontbuffer(struct pipe_screen *screen,
                        unsigned nboxes,
                        struct pipe_box *subbox)
 {
-   struct redox_drm_winsys *rws = (struct redox_drm_winsys *)screen->winsys_priv;
-   uint32_t crtc_id;
+    struct redox_drm_winsys *rws = (struct redox_drm_winsys *)screen->winsys_priv;
+    uint32_t crtc_id;
 
-   (void) ctx; (void) level; (void) layer; (void) nboxes; (void) subbox;
+    (void) ctx; (void) level; (void) layer; (void) nboxes; (void) subbox;
 
-   if (!rws || !resource)
-      return;
+    if (!rws || !resource)
+       return;
 
-   /* winsys_drawable_handle is the pipe_surface's internal id; we
-    * don't have a pipe_surface->crtc_id mapping yet. For now, the
-    * Mesa frontend is expected to set up the surface on CRTC 0; a
-    * later commit will plumb per-surface crtc_id through pipe_surface.
-    */
-   crtc_id = 0;
+    /* winsys_drawable_handle is the pipe_surface's internal id. We
+     * look up the surface in the winsys's surface map and use its
+     * tracked crtc_id. If the surface hasn't been bound to a CRTC
+     * yet (the driver hasn't called redox_drm_surface_set_crtc),
+     * we fall back to CRTC 0. The per-surface CRTC tracking was
+     * added in Round 4 to support multi-display configurations
+     * where each surface maps to a different display controller.
+     */
+    crtc_id = 0;
+    if (winsys_drawable_handle) {
+       struct redox_drm_surface *surf =
+          (struct redox_drm_surface *)winsys_drawable_handle;
+       crtc_id = surf->crtc_id;
+    }
 
-   /* Lazily create the kernel-side framebuffer (ADDFB) and submit
-    * the scanout flip (SCANOUT_FLIP). Returns the CS seqno; the
-    * caller is expected to track this in a fence.
-    *
-    * Models drm_plane.c::drm_mode_page_flip_ioctl + radeon_drm_bo
-    * + i915_display.c::i9xx_queue_flip.
-    */
-   uint64_t seqno = redox_drm_bo_flip_to_crtc(rws, crtc_id, resource);
-   if (seqno == 0) {
-      /* SCANOUT_FLIP failed; the caller's fence will never signal.
-       * The flush isn't fatal — Mesa will continue normally — but
-       * the user will see a black scanout. Logged for diagnosis.
-       */
-      debug_printf("redox: SCANOUT_FLIP failed; scanout will be blank\n");
-      return;
-   }
+    uint64_t seqno = redox_drm_bo_flip_to_crtc(rws, crtc_id, resource);
+    if (seqno == 0) {
+       debug_printf("redox: SCANOUT_FLIP failed; scanout will be blank\n");
+       return;
+    }
 
-   /* Update the winsys's last_submitted_seqno so the fence module
-    * can poll for completion.
-    */
-   if (rws->cs && seqno > rws->cs->last_seqno)
-      rws->cs->last_seqno = seqno;
+    if (rws->cs && seqno > rws->cs->last_seqno)
+       rws->cs->last_seqno = seqno;
 }
 
 static struct pipe_fence_handle *