drm/i915: dump the DMA fetch addr register on pre-gen6

It exists way back to gen2, bug got moved around on gen4 a bit.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -757,8 +757,8 @@ static void i915_ring_error_state(struct seq_file *m,
 	if (INTEL_INFO(dev)->gen >= 4)
 		seq_printf(m, "  INSTPS: 0x%08x\n", error->instps[ring]);
 	seq_printf(m, "  INSTPM: 0x%08x\n", error->instpm[ring]);
-	if (INTEL_INFO(dev)->gen >= 6) {
 	seq_printf(m, "  FADDR: 0x%08x\n", error->faddr[ring]);
+	if (INTEL_INFO(dev)->gen >= 6) {
 		seq_printf(m, "  FAULT_REG: 0x%08x\n", error->fault_reg[ring]);
 		seq_printf(m, "  SYNC_0: 0x%08x\n",
 			   error->semaphore_mboxes[ring][0]);

drivers/gpu/drm/i915/i915_irq.c

@@ -1029,7 +1029,6 @@ static void i915_record_ring_state(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	if (INTEL_INFO(dev)->gen >= 6) {
-		error->faddr[ring->id] = I915_READ(RING_DMA_FADD(ring->mmio_base));
 		error->fault_reg[ring->id] = I915_READ(RING_FAULT_REG(ring));
 		error->semaphore_mboxes[ring->id][0]
 			= I915_READ(RING_SYNC_0(ring->mmio_base));
@@ -1038,6 +1037,7 @@ static void i915_record_ring_state(struct drm_device *dev,
 	}
 
 	if (INTEL_INFO(dev)->gen >= 4) {
+		error->faddr[ring->id] = I915_READ(RING_DMA_FADD(ring->mmio_base));
 		error->ipeir[ring->id] = I915_READ(RING_IPEIR(ring->mmio_base));
 		error->ipehr[ring->id] = I915_READ(RING_IPEHR(ring->mmio_base));
 		error->instdone[ring->id] = I915_READ(RING_INSTDONE(ring->mmio_base));
@@ -1047,6 +1047,7 @@ static void i915_record_ring_state(struct drm_device *dev,
 			error->bbaddr = I915_READ64(BB_ADDR);
 		}
 	} else {
+		error->faddr[ring->id] = I915_READ(DMA_FADD_I8XX);
 		error->ipeir[ring->id] = I915_READ(IPEIR);
 		error->ipehr[ring->id] = I915_READ(IPEHR);
 		error->instdone[ring->id] = I915_READ(INSTDONE);

drivers/gpu/drm/i915/i915_reg.h

@@ -474,6 +474,7 @@
 #define INSTDONE	0x02090
 #define NOPID		0x02094
 #define HWSTAM		0x02098
+#define DMA_FADD_I8XX	0x020d0
 
 #define ERROR_GEN6	0x040a0