drm/i915: Differentiate between sw write location into ring and last hw read
We need to keep track of the last location we ask the hw to read up to
(RING_TAIL) separately from our last write location into the ring, so
that in the event of a GPU reset we do not tell the HW to proceed into
a partially written request (which can happen if that request is waiting
for an external signal before being executed).
v2: Refactor intel_ring_reset() (Mika)
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100144
Testcase: igt/gem_exec_fence/await-hang
Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests")
Fixes: d55ac5bf97c6 ("drm/i915: Defer transfer onto execution timeline to actual hw submission")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170425130049.26147-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
(cherry picked from commit e6ba9992de6c63fe86c028b4876338e1cb7dac34)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170615131129.3061-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 66a2b8b..513a0f4 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -49,7 +49,7 @@ static int __intel_ring_space(int head, int tail, int size)
void intel_ring_update_space(struct intel_ring *ring)
{
- ring->space = __intel_ring_space(ring->head, ring->tail, ring->size);
+ ring->space = __intel_ring_space(ring->head, ring->emit, ring->size);
}
static int
@@ -774,8 +774,8 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request)
i915_gem_request_submit(request);
- assert_ring_tail_valid(request->ring, request->tail);
- I915_WRITE_TAIL(request->engine, request->tail);
+ I915_WRITE_TAIL(request->engine,
+ intel_ring_set_tail(request->ring, request->tail));
}
static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
@@ -1316,11 +1316,23 @@ int intel_ring_pin(struct intel_ring *ring, unsigned int offset_bias)
return PTR_ERR(addr);
}
+void intel_ring_reset(struct intel_ring *ring, u32 tail)
+{
+ GEM_BUG_ON(!list_empty(&ring->request_list));
+ ring->tail = tail;
+ ring->head = tail;
+ ring->emit = tail;
+ intel_ring_update_space(ring);
+}
+
void intel_ring_unpin(struct intel_ring *ring)
{
GEM_BUG_ON(!ring->vma);
GEM_BUG_ON(!ring->vaddr);
+ /* Discard any unused bytes beyond that submitted to hw. */
+ intel_ring_reset(ring, ring->tail);
+
if (i915_vma_is_map_and_fenceable(ring->vma))
i915_vma_unpin_iomap(ring->vma);
else
@@ -1562,8 +1574,9 @@ void intel_legacy_submission_resume(struct drm_i915_private *dev_priv)
struct intel_engine_cs *engine;
enum intel_engine_id id;
+ /* Restart from the beginning of the rings for convenience */
for_each_engine(engine, dev_priv, id)
- engine->buffer->head = engine->buffer->tail;
+ intel_ring_reset(engine->buffer, 0);
}
static int ring_request_alloc(struct drm_i915_gem_request *request)
@@ -1616,7 +1629,7 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
unsigned space;
/* Would completion of this request free enough space? */
- space = __intel_ring_space(target->postfix, ring->tail,
+ space = __intel_ring_space(target->postfix, ring->emit,
ring->size);
if (space >= bytes)
break;
@@ -1641,8 +1654,8 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
{
struct intel_ring *ring = req->ring;
- int remain_actual = ring->size - ring->tail;
- int remain_usable = ring->effective_size - ring->tail;
+ int remain_actual = ring->size - ring->emit;
+ int remain_usable = ring->effective_size - ring->emit;
int bytes = num_dwords * sizeof(u32);
int total_bytes, wait_bytes;
bool need_wrap = false;
@@ -1678,17 +1691,17 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
if (unlikely(need_wrap)) {
GEM_BUG_ON(remain_actual > ring->space);
- GEM_BUG_ON(ring->tail + remain_actual > ring->size);
+ GEM_BUG_ON(ring->emit + remain_actual > ring->size);
/* Fill the tail with MI_NOOP */
- memset(ring->vaddr + ring->tail, 0, remain_actual);
- ring->tail = 0;
+ memset(ring->vaddr + ring->emit, 0, remain_actual);
+ ring->emit = 0;
ring->space -= remain_actual;
}
- GEM_BUG_ON(ring->tail > ring->size - bytes);
- cs = ring->vaddr + ring->tail;
- ring->tail += bytes;
+ GEM_BUG_ON(ring->emit > ring->size - bytes);
+ cs = ring->vaddr + ring->emit;
+ ring->emit += bytes;
ring->space -= bytes;
GEM_BUG_ON(ring->space < 0);
@@ -1699,7 +1712,7 @@ u32 *intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
int intel_ring_cacheline_align(struct drm_i915_gem_request *req)
{
int num_dwords =
- (req->ring->tail & (CACHELINE_BYTES - 1)) / sizeof(uint32_t);
+ (req->ring->emit & (CACHELINE_BYTES - 1)) / sizeof(uint32_t);
u32 *cs;
if (num_dwords == 0)