dix: add ability to link output slave gpus to the current gpu (v1.1)

Just add the interfaces to attach/detach output slaves, and
a linked list to keep track of them. Hook up the randr providers
list to include these slaves.

v1.1: add another assert to the add path.
Reviewed-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

dix/dispatch.c

@@ -3743,6 +3743,7 @@ static int init_screen(ScreenPtr pScreen, int i, Bool gpu)
     pScreen->CreateScreenResources = 0;
 
     xorg_list_init(&pScreen->unattached_list);
+    xorg_list_init(&pScreen->output_slave_list);
 
     /*
      * This loop gets run once for every Screen that gets added,
@@ -3909,3 +3910,19 @@ DetachUnboundGPU(ScreenPtr slave)
     slave->current_master = NULL;
 }
 
+void
+AttachOutputGPU(ScreenPtr pScreen, ScreenPtr new)
+{
+    assert(new->isGPU);
+    assert(!new->current_master);
+    xorg_list_add(&new->output_head, &pScreen->output_slave_list);
+    new->current_master = pScreen;
+}
+
+void
+DetachOutputGPU(ScreenPtr slave)
+{
+    assert(slave->isGPU);
+    xorg_list_del(&slave->output_head);
+    slave->current_master = NULL;
+}

include/screenint.h

@@ -76,6 +76,12 @@ AttachUnboundGPU(ScreenPtr pScreen, ScreenPtr new);
 extern _X_EXPORT void
 DetachUnboundGPU(ScreenPtr unbound);
 
+extern _X_EXPORT void
+AttachOutputGPU(ScreenPtr pScreen, ScreenPtr new);
+
+extern _X_EXPORT void
+DetachOutputGPU(ScreenPtr output);
+
 typedef struct _ColormapRec *ColormapPtr;
 
 #endif                          /* SCREENINT_H */

include/scrnintstr.h

@@ -485,6 +485,9 @@ typedef struct _Screen {
 
     ScreenPtr current_master;
 
+    struct xorg_list output_slave_list;
+    struct xorg_list output_head;
+
 } ScreenRec;
 
 static inline RegionPtr

randr/rrprovider.c

@@ -72,6 +72,10 @@ ProcRRGetProviders (ClientPtr client)
 
     if (pScrPriv->provider)
         total_providers++;
+    xorg_list_for_each_entry(iter, &pScreen->output_slave_list, output_head) {
+        pScrPriv = rrGetScrPriv(iter);
+        total_providers += pScrPriv->provider ? 1 : 0;
+    }
     xorg_list_for_each_entry(iter, &pScreen->unattached_list, unattached_head) {
         pScrPriv = rrGetScrPriv(iter);
         total_providers += pScrPriv->provider ? 1 : 0;
@@ -105,6 +109,9 @@ ProcRRGetProviders (ClientPtr client)
 
         providers = (RRProvider *)extra;
         ADD_PROVIDER(pScreen);
+        xorg_list_for_each_entry(iter, &pScreen->output_slave_list, output_head) {
+            ADD_PROVIDER(iter);
+        }
         xorg_list_for_each_entry(iter, &pScreen->unattached_list, unattached_head) {
             ADD_PROVIDER(iter);
         }