drm/i915: SNB BLT workaround
On some stepping of SNB cpu, the first command to be parsed in BLT
command streamer should be MI_BATCHBUFFER_START otherwise the GPU
may hang.
Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
[ickle: rebased for -next]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 390aa21..a0702b6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -658,6 +658,9 @@
drm_gem_object_unreference(ring->gem_object);
ring->gem_object = NULL;
+ if (ring->cleanup)
+ ring->cleanup(ring);
+
cleanup_status_page(ring);
}
@@ -877,19 +880,133 @@
/* do nothing */
}
+
+/* Workaround for some stepping of SNB,
+ * each time when BLT engine ring tail moved,
+ * the first command in the ring to be parsed
+ * should be MI_BATCH_BUFFER_START
+ */
+#define NEED_BLT_WORKAROUND(dev) \
+ (IS_GEN6(dev) && (dev->pdev->revision < 8))
+
+static inline struct drm_i915_gem_object *
+to_blt_workaround(struct intel_ring_buffer *ring)
+{
+ return ring->private;
+}
+
+static int blt_ring_init(struct intel_ring_buffer *ring)
+{
+ if (NEED_BLT_WORKAROUND(ring->dev)) {
+ struct drm_i915_gem_object *obj;
+ u32 __iomem *ptr;
+ int ret;
+
+ obj = to_intel_bo(i915_gem_alloc_object(ring->dev, 4096));
+ if (obj == NULL)
+ return -ENOMEM;
+
+ ret = i915_gem_object_pin(&obj->base, 4096, true, false);
+ if (ret) {
+ drm_gem_object_unreference(&obj->base);
+ return ret;
+ }
+
+ ptr = kmap(obj->pages[0]);
+ iowrite32(MI_BATCH_BUFFER_END, ptr);
+ iowrite32(MI_NOOP, ptr+1);
+ kunmap(obj->pages[0]);
+
+ ret = i915_gem_object_set_to_gtt_domain(&obj->base, false);
+ if (ret) {
+ i915_gem_object_unpin(&obj->base);
+ drm_gem_object_unreference(&obj->base);
+ return ret;
+ }
+
+ ring->private = obj;
+ }
+
+ return init_ring_common(ring);
+}
+
+static int blt_ring_begin(struct intel_ring_buffer *ring,
+ int num_dwords)
+{
+ if (ring->private) {
+ int ret = intel_ring_begin(ring, num_dwords+2);
+ if (ret)
+ return ret;
+
+ intel_ring_emit(ring, MI_BATCH_BUFFER_START);
+ intel_ring_emit(ring, to_blt_workaround(ring)->gtt_offset);
+
+ return 0;
+ } else
+ return intel_ring_begin(ring, 4);
+}
+
+static void blt_ring_flush(struct intel_ring_buffer *ring,
+ u32 invalidate_domains,
+ u32 flush_domains)
+{
+ if (blt_ring_begin(ring, 4) == 0) {
+ intel_ring_emit(ring, MI_FLUSH_DW);
+ intel_ring_emit(ring, 0);
+ intel_ring_emit(ring, 0);
+ intel_ring_emit(ring, 0);
+ intel_ring_advance(ring);
+ }
+}
+
+static int
+blt_ring_add_request(struct intel_ring_buffer *ring,
+ u32 *result)
+{
+ u32 seqno;
+ int ret;
+
+ ret = blt_ring_begin(ring, 4);
+ if (ret)
+ return ret;
+
+ seqno = i915_gem_get_seqno(ring->dev);
+
+ intel_ring_emit(ring, MI_STORE_DWORD_INDEX);
+ intel_ring_emit(ring, I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT);
+ intel_ring_emit(ring, seqno);
+ intel_ring_emit(ring, MI_USER_INTERRUPT);
+ intel_ring_advance(ring);
+
+ DRM_DEBUG_DRIVER("%s %d\n", ring->name, seqno);
+ *result = seqno;
+ return 0;
+}
+
+static void blt_ring_cleanup(struct intel_ring_buffer *ring)
+{
+ if (!ring->private)
+ return;
+
+ i915_gem_object_unpin(ring->private);
+ drm_gem_object_unreference(ring->private);
+ ring->private = NULL;
+}
+
static const struct intel_ring_buffer gen6_blt_ring = {
.name = "blt ring",
.id = RING_BLT,
.mmio_base = BLT_RING_BASE,
.size = 32 * PAGE_SIZE,
- .init = init_ring_common,
+ .init = blt_ring_init,
.write_tail = ring_write_tail,
- .flush = gen6_ring_flush,
- .add_request = ring_add_request,
+ .flush = blt_ring_flush,
+ .add_request = blt_ring_add_request,
.get_seqno = ring_status_page_get_seqno,
.user_irq_get = blt_ring_get_user_irq,
.user_irq_put = blt_ring_put_user_irq,
.dispatch_execbuffer = gen6_ring_dispatch_execbuffer,
+ .cleanup = blt_ring_cleanup,
};
int intel_init_render_ring_buffer(struct drm_device *dev)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index acd2337..68043f1 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -55,6 +55,7 @@
struct drm_i915_gem_execbuffer2 *exec,
struct drm_clip_rect *cliprects,
uint64_t exec_offset);
+ void (*cleanup)(struct intel_ring_buffer *ring);
/**
* List of objects currently involved in rendering from the
@@ -90,6 +91,8 @@
wait_queue_head_t irq_queue;
drm_local_map_t map;
+
+ void *private;
};
static inline u32