drm/i915: move vbetool invoked ier stuff

This extra bit of interrupt enabling code doesn't belong in the wait
seqno function. If anything we should pull it out to a helper so the
throttle code can also use it. The history is a bit vague, but I am
going to attempt to just dump it, unless someone can argue otherwise.

Removing this allows for a shared lock free wait seqno function. To keep
tabs on this issue though, the IER value is stored on error capture
(recommended by Chris Wilson)

v2: fixed typo EIR->IER (Ben)
Fix some white space (Ben)
Move IER capture to globally instead of per ring (Ben)
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: ier is a 16 bit reg on gen2!]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -712,6 +712,7 @@ static int i915_error_state(struct seq_file *m, void *unused)
 		   error->time.tv_usec);
 	seq_printf(m, "PCI ID: 0x%04x\n", dev->pci_device);
 	seq_printf(m, "EIR: 0x%08x\n", error->eir);
+	seq_printf(m, "IER: 0x%08x\n", error->ier);
 	seq_printf(m, "PGTBL_ER: 0x%08x\n", error->pgtbl_er);
 
 	for (i = 0; i < dev_priv->num_fence_regs; i++)

drivers/gpu/drm/i915/i915_drv.h

@@ -173,6 +173,7 @@ struct intel_display_error_state;
 struct drm_i915_error_state {
 	u32 eir;
 	u32 pgtbl_er;
+	u32 ier;
 	u32 pipestat[I915_MAX_PIPES];
 	u32 tail[I915_NUM_RINGS];
 	u32 head[I915_NUM_RINGS];

drivers/gpu/drm/i915/i915_gem.c

@@ -1828,7 +1828,6 @@ i915_wait_request(struct intel_ring_buffer *ring,
 		  uint32_t seqno)
 {
 	drm_i915_private_t *dev_priv = ring->dev->dev_private;
-	u32 ier;
 	int ret = 0;
 
 	BUG_ON(seqno == 0);
@@ -1863,19 +1862,6 @@ i915_wait_request(struct intel_ring_buffer *ring,
 	}
 
 	if (!i915_seqno_passed(ring->get_seqno(ring), seqno)) {
-		if (HAS_PCH_SPLIT(ring->dev))
-			ier = I915_READ(DEIER) | I915_READ(GTIER);
-		else if (IS_VALLEYVIEW(ring->dev))
-			ier = I915_READ(GTIER) | I915_READ(VLV_IER);
-		else
-			ier = I915_READ(IER);
-		if (!ier) {
-			DRM_ERROR("something (likely vbetool) disabled "
-				  "interrupts, re-enabling\n");
-			ring->dev->driver->irq_preinstall(ring->dev);
-			ring->dev->driver->irq_postinstall(ring->dev);
-		}
-
 		trace_i915_gem_request_wait_begin(ring, seqno);
 
 		ring->waiting_seqno = seqno;

drivers/gpu/drm/i915/i915_irq.c

@@ -1122,6 +1122,16 @@ static void i915_capture_error_state(struct drm_device *dev)
 
 	error->eir = I915_READ(EIR);
 	error->pgtbl_er = I915_READ(PGTBL_ER);
+
+	if (HAS_PCH_SPLIT(dev))
+		error->ier = I915_READ(DEIER) | I915_READ(GTIER);
+	else if (IS_VALLEYVIEW(dev))
+		error->ier = I915_READ(GTIER) | I915_READ(VLV_IER);
+	else if (IS_GEN2(dev))
+		error->ier = I915_READ16(IER);
+	else
+		error->ier = I915_READ(IER);
+
 	for_each_pipe(pipe)
 		error->pipestat[pipe] = I915_READ(PIPESTAT(pipe));