On Fri, Sep 19, 2014 at 08:58:58PM +0300, Ville Syrjälä wrote:
> On Wed, Jun 18, 2014 at 12:23:14PM +0100, Chris Wilson wrote:
> > Since mmio-flips do not occur on the suggested ring, we are introducing
> > an extra sync operation where none is required. Pass the current
> > obj->ring, which is what mmio flip will use, to pin_to_display_plane so
> > that we emit the appropriate synchronisation (none).
> >
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> I had a vague recollection that I had seen something like this and now I
> found it...
>
> The patch could use a rebase I think, and perhaps it could use a boolean
> to avoid duplicating the buffer pinning in two place? I was thinking
> something like:
>
> ring = whatever;
> bool mmio_flip = use_mmio_flip(ring);
> if (mmio_flip)
> ring = obj->ring;
> pin_and_fence(ring);
> ...
> if (mmio_flip)
> ...
> else
> ...
This is the final version:
if (use_mmio_flip(engine, obj, page_flip_flags)) {
rq = i915_request_get(obj->last_write.request);
ret = intel_pin_and_fence_fb_obj(dev, obj, rq);
if (ret)
goto cleanup_rq;
work->gtt_offset =
i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset;
ret = intel_queue_mmio_flip(intel_crtc, rq);
if (ret)
goto cleanup_unpin;
} else {
struct intel_context *ctx = engine->default_context;
if (obj->last_write.request)
ctx = obj->last_write.request->ctx;
rq = intel_engine_alloc_request(engine, ctx);
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
goto cleanup_pending;
}
ret = intel_pin_and_fence_fb_obj(dev, obj, rq);
if (ret)
goto cleanup_rq;
work->gtt_offset =
i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset;
ret = dev_priv->display.queue_flip(rq, intel_crtc, fb, obj,
page_flip_flags);
if (ret)
goto cleanup_unpin;
intel_mark_page_flip_active(intel_crtc);
ret = i915_request_commit(rq);
if (ret)
goto cleanup_unpin;
}
which your suggestion would make
do_mmio = use_mmio_flip(engine, obj, page_flip_flags);
if (do_mmio) {
rq = i915_request_get(obj->last_write.request);
} else {
struct intel_context *ctx = engine->default_context;
if (obj->last_write.request)
ctx = obj->last_write.request->ctx;
rq = intel_engine_alloc_request(engine, ctx);
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
goto cleanup_pending;
}
]
ret = intel_pin_and_fence_fb_obj(dev, obj, rq);
if (ret)
goto cleanup_rq;
work->gtt_offset =
i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset;
if (do_mmio) {
ret = intel_queue_mmio_flip(intel_crtc, rq);
} else {
ret = dev_priv->display.queue_flip(rq, intel_crtc, fb, obj,
page_flip_flags);
if (ret == 0) {
intel_mark_page_flip_active(intel_crtc);
ret = i915_request_commit(rq);
}
}
if (ret)
goto cleanup_unpin;
Here, I definitely want to keep the allocated request tied to the
i915_request_commit(), so I favour the duplication in this case.
Unless I push the queue_flip tail down again, i.e.
if (do_mmio)
ret = intel_queue_mmio_flip(intel_crtc, rq);
else
ret = intel_queue_page_flip(rq, intel_crtc, fb, obj,
page_flip_flags);
if (ret)
goto cleanup_unpin;
or push do_mmio into page_flip_flags and have a single function here?
page_flip_flags |= use_mmio_flip(engine, obj, page_flip_flags);
rq = intel_page_flip_alloc_request(engine, obj, page_flip_flags);
if (IS_ERR(rq)) {
ret = PTR_ERR(rq);
goto cleanup_pending;
}
ret = intel_pin_and_fence_fb_obj(dev, obj, rq);
if (ret)
goto cleanup_rq;
work->gtt_offset =
i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset;
ret = intel_page_flip_queue(rq, intel_crtc, fb, obj, page_flip_flags);
if (ret)
goto cleanup_unpin;
Maybe, just now worrying about hiding too much magic behind the scenes.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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