[PATCH 08/10] drm/i915: real wait seqno with timeout

Ben Widawsky
2012-04-21T01:25:29Z

Move the final interesting chunk from i915_wait_seqno into a timed
variant. The timed variant can take a NULL or 0 timeout argument to
preserve the old behavior, and this allowing the old (still useful
function) to call directly into the timed variant.

This code does not require struct_mutex, therefore it can wait on events
without holding the lock.

Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com>
---
drivers/gpu/drm/i915/i915_gem.c | 53 ++++++++++++++++++++++++++-------------
1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7bfad04..e446d9c 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1879,6 +1879,40 @@ static int __wait_seqno(struct intel_ring_buffer *ring, u32 seqno,
}
}

+static int
+i915_seqno_wait_timed(struct intel_ring_buffer *ring, u32 seqno,
+ bool interruptible, long *timeout)
+{
+ bool wait_forever = false;
+ int ret = 0;
+
+ BUG_ON(seqno == ring->outstanding_lazy_request);
+
+ if (timeout == NULL || ((*timeout) < 0))
+ wait_forever = true;
+
+ if (!i915_seqno_passed(ring->get_seqno(ring), seqno)) {
+ trace_i915_gem_request_wait_begin(ring, seqno);
+
+ if (WARN_ON(!ring->irq_get(ring)))
+ return -EBUSY;
+
+ do {
+ long time = wait_forever ? SEQNO_WAIT_DEFAULT : *timeout;
+ ret = __wait_seqno(ring, seqno,
+ interruptible,
+ &time);
+ if (ret == 0 && timeout)
+ *timeout = time;
+ } while (ret == -ETIME && wait_forever);
+
+ ring->irq_put(ring);
+ trace_i915_gem_request_wait_end(ring, seqno);
+ }
+
+ return ret;
+}
+
/**
* Waits for a sequence number to be signaled, and cleans up the
* request and object lists appropriately for that event.
@@ -1920,23 +1954,8 @@ i915_wait_request(struct intel_ring_buffer *ring,

seqno = request->seqno;
}
-
- if (!i915_seqno_passed(ring->get_seqno(ring), seqno)) {
- trace_i915_gem_request_wait_begin(ring, seqno);
-
- if (WARN_ON(!ring->irq_get(ring)))
- return -EBUSY;
-
- do {
- long time = SEQNO_WAIT_DEFAULT;
- ret = __wait_seqno(ring, seqno,
- dev_priv->mm.interruptible,
- &time);
- } while (ret == -ETIME);
-
- ring->irq_put(ring);
- trace_i915_gem_request_wait_end(ring, seqno);
- }
+ ret = i915_seqno_wait_timed(ring, seqno, dev_priv->mm.interruptible,
+ NULL);
if (atomic_read(&dev_priv->mm.wedged))
ret = -EAGAIN;

--
1.7.10