nouveau: hide some debugging messages behind environment variable

They spam console, but are not very useful - hide them behind
NOUVEAU_MESA_DEBUG environment variable.

src/gallium/drivers/nouveau/nouveau_buffer.c

@@ -431,7 +431,8 @@ nouveau_buffer_migrate(struct nouveau_context *nv,
          /* keep a system memory copy of our data in case we hit a fallback */
          if (!nouveau_buffer_data_fetch(buf, buf->bo, buf->offset, size))
             return FALSE;
-         debug_printf("migrating %u KiB to VRAM\n", size / 1024);
+         if (nouveau_mesa_debug)
+            debug_printf("migrating %u KiB to VRAM\n", size / 1024);
       }
 
       offset = buf->offset;

src/gallium/drivers/nouveau/nouveau_mm.c

@@ -145,8 +145,9 @@ mm_slab_new(struct nouveau_mman *cache, int chunk_order)
 
    cache->allocated += size;
 
-   debug_printf("MM: new slab, total memory = %"PRIu64" KiB\n",
-                cache->allocated / 1024);
+   if (nouveau_mesa_debug)
+      debug_printf("MM: new slab, total memory = %"PRIu64" KiB\n",
+                   cache->allocated / 1024);
 
    return PIPE_OK;
 }

src/gallium/drivers/nouveau/nouveau_screen.c

@@ -10,6 +10,7 @@
 
 #include <stdio.h>
 #include <errno.h>
+#include <stdlib.h>
 
 #include "nouveau/nouveau_bo.h"
 #include "nouveau/nouveau_mm.h"
@@ -21,6 +22,8 @@
 #include "state_tracker/drm_driver.h"
 #include "util/u_simple_screen.h"
 
+int nouveau_mesa_debug = 0;
+
 static const char *
 nouveau_screen_get_name(struct pipe_screen *pscreen)
 {
@@ -202,6 +205,10 @@ nouveau_screen_init(struct nouveau_screen *screen, struct nouveau_device *dev)
 	struct pipe_screen *pscreen = &screen->base;
 	int ret;
 
+	char *nv_dbg = getenv("NOUVEAU_MESA_DEBUG");
+	if (nv_dbg)
+	   nouveau_mesa_debug = atoi(nv_dbg);
+
 	ret = nouveau_channel_alloc(dev, 0xbeef0201, 0xbeef0202,
 				    512*1024, &screen->channel);
 	if (ret)

src/gallium/drivers/nouveau/nouveau_screen.h

@@ -5,6 +5,8 @@
 #include "util/u_memory.h"
 typedef uint32_t u32;
 
+extern int nouveau_mesa_debug;
+
 struct nouveau_bo;
 
 struct nouveau_screen {

src/gallium/drivers/nv50/nv50_screen.c

@@ -502,8 +502,9 @@ nv50_screen_create(struct pipe_winsys *ws, struct nouveau_device *dev)
 
    screen->tls_size = tls_space * max_warps * 32;
 
-   debug_printf("max_warps = %i, tls_size = %"PRIu64" KiB\n",
-                max_warps, screen->tls_size >> 10);
+   if (nouveau_mesa_debug)
+      debug_printf("max_warps = %i, tls_size = %"PRIu64" KiB\n",
+                     max_warps, screen->tls_size >> 10);
 
    ret = nouveau_bo_new(dev, NOUVEAU_BO_VRAM, 1 << 16, screen->tls_size,
                         &screen->tls_bo);