On 26/11/2014 09:23, Daniel Vetter wrote:
On Mon, Nov 24, 2014 at 06:49:34PM +0000, John.C.Harrison@xxxxxxxxx wrote:
From: John Harrison <John.C.Harrison@xxxxxxxxx>
Converted the mmio_flip 'seqno' value to be a request structure as part of the
on going seqno to request changes. This includes reference counting the request
being saved away to ensure it can not be retired and freed while the flip code
is still waiting on it.
v2: Used the IRQ friendly request dereference call in the notify handler as that
code is called asynchronously without holding any useful mutex locks.
For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>
Reviewed-by: Thomas Daniel <Thomas.Daniel@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_display.c | 20 ++++++++++----------
drivers/gpu/drm/i915/intel_drv.h | 3 +--
2 files changed, 11 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 097e8a1..cbf3cb7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9550,18 +9550,19 @@ static void intel_mmio_flip_work_func(struct work_struct *work)
{
struct intel_crtc *intel_crtc =
container_of(work, struct intel_crtc, mmio_flip.work);
- struct intel_engine_cs *ring;
- uint32_t seqno;
-
- seqno = intel_crtc->mmio_flip.seqno;
- ring = intel_crtc->mmio_flip.ring;
+ struct intel_mmio_flip *mmio_flip;
- if (seqno)
- WARN_ON(__i915_wait_seqno(ring, seqno,
+ mmio_flip = &intel_crtc->mmio_flip;
+ if (mmio_flip->req)
+ WARN_ON(__i915_wait_seqno(i915_gem_request_get_ring(mmio_flip->req),
+ i915_gem_request_get_seqno(mmio_flip->req),
intel_crtc->reset_counter,
false, NULL, NULL) != 0);
intel_do_mmio_flip(intel_crtc);
+ if (mmio_flip->req)
+ i915_gem_request_unreference_irq(mmio_flip->req);
Can't we just grab dev->struct_mutex around here and reuse the normal
request_unref? That would allow us to ditch all the unref_irq complexity.
-Daniel
The unref_irq is needed for the flip_queued_req as that is still
dereferenced from interrupt time. Possibly this one could now be
downgraded to a mutex lock but before the recent rebase, the mmio_flip
request was also being dereferenced at interrupt time so definitely
needed the irq friendly version. Is there a worry that waiting for the
mutex lock could stall the flip handler so long that it misses the next
flip?
+ mmio_flip->req = NULL;
}
static int intel_queue_mmio_flip(struct drm_device *dev,
@@ -9573,9 +9574,8 @@ static int intel_queue_mmio_flip(struct drm_device *dev,
{
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
- intel_crtc->mmio_flip.seqno =
- i915_gem_request_get_seqno(obj->last_write_req);
- intel_crtc->mmio_flip.ring = obj->ring;
+ i915_gem_request_assign(&intel_crtc->mmio_flip.req,
+ obj->last_write_req);
schedule_work(&intel_crtc->mmio_flip.work);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 44b153c5..2755532 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -406,8 +406,7 @@ struct intel_pipe_wm {
};
struct intel_mmio_flip {
- u32 seqno;
- struct intel_engine_cs *ring;
+ struct drm_i915_gem_request *req;
struct work_struct work;
};
--
1.7.9.5
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