Index: shared-core/nouveau_drv.h
===================================================================
--- shared-core.orig/nouveau_drv.h	2006-11-29 22:30:40.000000000 +0100
+++ shared-core/nouveau_drv.h	2006-12-04 19:12:35.000000000 +0100
@@ -75,6 +75,9 @@
 	struct nouveau_object *cmdbuf_obj;
 	/* objects belonging to this fifo */
 	struct nouveau_object *objs;
+
+	/* XXX move this in PGRAPH struct */
+	uint32_t pgraph_ctx_user;
 };
 
 struct nouveau_object_store
Index: shared-core/nouveau_fifo.c
===================================================================
--- shared-core.orig/nouveau_fifo.c	2006-11-29 22:32:20.000000000 +0100
+++ shared-core/nouveau_fifo.c	2006-12-04 19:12:33.000000000 +0100
@@ -165,6 +165,7 @@
 	NV_WRITE(NV_PFIFO_CACH1_PUL0, 0x00000001);
 	NV_WRITE(NV_PFIFO_CACH1_PUL1, 0x00000001);
 
+	//XXX we assume that channel 0 is the first to use PGRAPH
 	NV_WRITE(NV_PGRAPH_CTX_USER, 0x0);
 	NV_WRITE(NV_PFIFO_DELAY_0, 0xff /* retrycount*/ );
 	if (dev_priv->card_type >= NV_40)
@@ -418,6 +419,7 @@
 	init->channel  = i;
 	init->put_base = i*dev_priv->cmdbuf_ch_size * 0;
 	dev_priv->cur_fifo = init->channel;
+	dev_priv->fifos[i].pgraph_ctx_user = i << 24;
 
 	nouveau_wait_for_idle(dev);
 
Index: shared-core/nouveau_irq.c
===================================================================
--- shared-core.orig/nouveau_irq.c	2006-11-29 22:42:04.000000000 +0100
+++ shared-core/nouveau_irq.c	2006-12-04 19:16:11.000000000 +0100
@@ -240,21 +240,31 @@
 static void nouveau_nv10_context_switch(drm_device_t *dev)
 {
 	drm_nouveau_private_t *dev_priv = dev->dev_private;
-	int channel;
+	int channel, channel_old;
 
 	channel=NV_READ(NV_PFIFO_CACH1_PSH1)&(nouveau_fifo_number(dev)-1);
-	/* 2-channel commute */
-//	if (channel==0)
-//		channel=1;
-//	else
-//		channel=0;
-//	dev_priv->cur_fifo=channel;
-
-//	NV_WRITE(NV_PGRAPH_CTX_CONTROL, 0x10000100);
-	NV_WRITE(NV_PGRAPH_CTX_USER, NV_READ(NV_PGRAPH_CTX_USER)|0x1F000000);
-//	NV_WRITE(NV_PGRAPH_FFINTFC_ST2, NV_READ(NV_PGRAPH_FFINTFC_ST2)&0xCFFFFFFF);
-	/* touch PGRAPH_CTX_SWITCH* here ? */
-	NV_WRITE(NV_PGRAPH_CTX_CONTROL, 0x10000100);
+	channel_old = (NV_READ(NV_PGRAPH_CTX_USER) >> 24) & (nouveau_fifo_number(dev)-1);
+
+	DRM_INFO("NV: PGRAPH context switch interrupt channel %x -> %x\n",channel_old, channel);
+
+	NV_WRITE(NV_PGRAPH_FIFO,0x0);
+	NV_WRITE(NV_PFIFO_CACH1_PUL0, 0x00000000);
+	NV_WRITE(NV_PFIFO_CACH1_PUL1, 0x00000000);
+	NV_WRITE(NV_PFIFO_CACHES, 0x00000000);
+
+	dev_priv->fifos[channel_old].pgraph_ctx_user = NV_READ(NV_PGRAPH_CTX_USER);
+	//XXX save PGRAPH context
+	NV_WRITE(NV_PGRAPH_CTX_CONTROL, 0x10000000);
+	NV_WRITE(NV_PGRAPH_CTX_USER, dev_priv->fifos[channel].pgraph_ctx_user);
+	//XXX restore PGRAPH context
+
+	NV_WRITE(NV_PGRAPH_FFINTFC_ST2, NV_READ(NV_PGRAPH_FFINTFC_ST2)&0xCFFFFFFF);
+	NV_WRITE(NV_PGRAPH_CTX_CONTROL, 0x10010100);
+
+	NV_WRITE(NV_PFIFO_CACH1_PUL0, 0x00000001);
+	NV_WRITE(NV_PFIFO_CACH1_PUL1, 0x00000001);
+	NV_WRITE(NV_PFIFO_CACHES, 0x00000001);
+	NV_WRITE(NV_PGRAPH_FIFO,0x1);
 }
 
 static void nouveau_pgraph_irq_handler(drm_device_t *dev)
@@ -339,7 +349,7 @@
 
 	if (status & NV_PGRAPH_INTR_CONTEXT_SWITCH) {
 		uint32_t channel=NV_READ(NV_PFIFO_CACH1_PSH1)&(nouveau_fifo_number(dev)-1);
-		DRM_INFO("NV: PGRAPH context switch interrupt channel %x\n",channel);
+		DRM_INFO("NV: PGRAPH context switch interrupt channel %x\n", channel);
 		switch(dev_priv->card_type)
 		{
 			case NV_04: